New African Knife fish not eating/RMF  10/4/09
Hello,
<Hi there>
Two days ago I purchased an African Knife fish after researching for quite some time and visiting pet stores.
<Xenomystus nigri... one of my fave fishes>
I purchased a 55 gallon aquarium setup and cycled it for ten days,
<This is a quick cycle>
took a water sample to be tested, and finally purchased my knife fish. It is quite healthy (busy at night and still in the day.) It has plenty of hiding places, but does not seem the slightest bit inclined to eat. So far
I have offered him frozen bloodworms, earthworms, and tropical flakes at night when he becomes active. He is about five inches and very healthy. I have searched the web diligently, finding only similar instances where refusing to eat was a problem and have read that larger knife fish can be difficult feeders. I was hoping for some suggestions on how to get him interested in feeding, because I would really hate to lose the fish I was soo keen on keeping.
<Mmm, well... am not sure this system is fully cycled, nor the fish all the way settled in...>
Thank you,
Stephanie
<Do try some form (frozen/defrosted, freeze-dried (stuck to the side low against the inside viewing panel/glass) or live Tubificid worms to get this fish started on captive foods... And do search again on the Net using the scientific name. Bob Fenner>

New African Knife fish not eating/Neale  10/4/09
Hello,
<Hello,>
Two days ago I purchased an African Knife fish after researching for quite some time and visiting pet stores. I purchased a 55 gallon aquarium setup and cycled it for ten days, took a water sample to be tested, and finally purchased my knife fish. It is quite healthy (busy at night and still in the day.) It has plenty of hiding places, but does not seem the slightest bit inclined to eat.
<He will... just give it time.>
So far I have offered him frozen bloodworms, earthworms, and tropical flakes at night when he becomes active.
<Flakes are a bit of a non-runner to be honest. But earthworms should work.
Make sure they're of adequate size, and of course, since these are nocturnal fish, offer them at night, with the tank lights out. Wet-frozen bloodworms will be taken too.>
He is about five inches and very healthy. I have searched the web diligently, finding only similar instances where refusing to eat was a problem and have read that larger knife fish can be difficult feeders.
<Xenomystus are not usually fussy, and provided water quality is good, he should eat. It normally takes longer than 10 days for a tank to cycle, so I'm suspicious of that. How did you cycle the tank? What source of ammonia did you use? Simply running the tank without fish has no cycling effect at all. You must provide ammonia for bacteria to use, otherwise the filter can't mature. The usual options are to either add small doses of household ammonia, or else to add flake food every day to the aquarium (as the flake rots, it produces ammonia, and that feeds the bacteria). Either way, it is normally 7-10 days for the ammonia to spike and start leveling off, but a good three weeks before the nitrite levels spike and drop down to zero. Use a nitrite test kit, check the nitrite level, and if it isn't zero, that's the problem.>
I was hoping for some suggestions on how to get him interested in feeding, because I would really hate to loose the fish I was soo keen on keeping.
Thank you,
Stephanie
<Cheers, Neale.>

Re: New African Knife fish not eating  10/5/09
Thank you so much for responding,
<My pleasure.>
To cycle my tank, I used AquaSafe for the heavy metals and in the next ten days I fed the tank with tropical flakes.
<Well, adding the flakes should work. But I'd be staggered if it only took 10 days to cycle the tank. Three to six weeks is normal. My gut feeling is your aquarium isn't cycled, and until the ammonia and nitrite levels hit zero, you'll have some problems. Non-zero levels of ammonia and nitrite stress fish, and among other things, put them off their food.>
I had a sample of the water tested for nitrates and the man that showed me how, explained that it was at zero.
<Nitrate -- with an "a" -- is largely irrelevant here. Unless you have very high levels, freshwater fish generally don't care about nitrate levels.
It's nitrite -- with an "i" -- that matters, and above zero, this most certainly is toxic to fish.>
I will try Tubifex tonight, and hopefully he will give in.
<Would actually buy a nitrite test kit first, and check the nitrite level.>
Thank you soo much for your help!-Stephanie
<Cheers, Neale.>

Re: New African Knife fish not eating  10/5/09
Thank you for responding! I cycled the tank using AquaSafe and feeding it for ten days like there were fish in it and when I had my sample tested, the nitrates read zero,
<... actually, NO3 should be accumulating if the system is cycling...>
but perhaps he is just not quite settled in yet. I have bought some Tubifex worms and I will give these a try tonight. Thank you soo much for your help!
-Stephanie
<Do read on WWM re biofiltration, cycling. BobF>

Re: New African Knife fish not eating  10/5/09
I took your advice and bought a good test kit, and determined the following: Nitrites are reading 0, Nitrates are 80-160, hardness is 25 (very soft), chlorine is 0, Total Alkalinity is 180-300, and pH is about 7.4-8.4 (Alkaline).
<Mostly sounds within the tolerances of this species. That said, the pH between 7.4 and 8.4 covers a lot of ground: an increase of 1.0 on the pH scale corresponds to a ten-fold increase in acidity or alkalinity. I'm
assuming this test kit is one with strips: while easy to use and certainly inexpensive, they are notoriously difficult to read and consequently can be unreliable. In any case, if you can have the pet shop confirm with a liquid test kit what the carbonate hardness (alkalinity) might be, and what the pH actually is, then that would be very useful.>
Since Nitrites are zero, should I not be concerned about the water quality?
<I'm still skeptical that you were able to complete the cycle in ten days... that's really a very short period of time (unless of course you added mature filter media from another aquarium). So I'd be sensitive to
the idea nitrite and ammonia levels might not be as low as you think. Try a test 2-3 times in one day; once first thing in the morning, another immediately after feeding, and then another a couple of hours thereafter.
If these are still zero, then yes, you are probably fine.>
Will this water quality contribute to the knife fish's lack of appetite?
<I'd try and pin down the pH. Xenomystus will do fine at pH 7.5, and should remain healthy even as high as pH 8. But above pH 8, and certainly at pH 8.4, it is out of its comfort zone.>
Thank you again for helping me!
<My pleasure.>
-Stephanie
<Cheers, Neale.>
<<I think Neale (or I) mis-read the Nitrate reading... 80-160 ppm is WAY too high. Please read here re importance and reducing: http://wetwebmedia.com/FWSubWebIndex/fwnitrates.htm
and the linked files above. Bob Fenner>> 

Re: New African Knife fish not eating: MORE... & FW NO3 f'  - 10/05/2009
<<I think Neale (or I) mis-read the Nitrate reading... 80-160 ppm is WAY too high. Please read here re importance and reducing:
http://wetwebmedia.com/FWSubWebIndex/fwnitrates.htm
and the linked files above. Bob Fenner>>
<Bob, you are quite right. I missed that: in fact I've never even heard of nitrate levels that high. Stephanie, you need to do a big water change today, and another tomorrow, I'd say 50% each time. Did you do water
changes while cycling the tank? You need to, otherwise the nitrate just builds up. Don't feed the fish. Review carefully before you start feeding how much you're adding. With luck, once the nitrate drops to below 50 mg/l, and preferably below 20 mg/l, you'll find the Xenomystus behaves much more normally. Feed, sparingly, small morsels of food. Initially at least, maybe one earthworm, every other night. Cheers, Neale.>

Re: New African Knife fish not eating: MORE... & FW NO3 f' - 10/05/2009
Oh, wow, I am on my way to doing a water change, but before I did, just out of curiosity, I tested the tap water and noticed that the Nitrates are equally high coming out of the tap! I have a Culligan water filter and I tested it as well with absolute opposite results... Should I consider using the filtered water instead? There were no nitrates present at all, the water was a bit softer and not as alkaline. The Xenomystus at an earthworm last night, so he is giving in, but I feel the water is still stressing him. Thank you again!
-Stephanie
<... Please read where you were referred to. I would NOT drink this water until it is tested by a professional. I would NOT use salt-recharged filter water... ALL this is gone over on WWM. Bob Fenner>

Re: New African Knife fish not eating: MORE... & FW NO3 f' - 10/05/2009
<... Please read where you were referred to. I would NOT drink this water until it is tested by a professional. I would NOT use salt-recharged filter water... ALL this is gone over on WWM. Bob Fenner>
<<Within the EU at least, the upper level of nitrate that is considered safe to drink is 50 mg/l; above that, your water supplier is *obliged by law* to act. It sounds as if your water is contaminated, e.g., by
agricultural run-off (the source of ~70% nitrate in UK water supplies, at least). As Bob says, this should NOT be treated as drinking water. Babies in particular are at particular risk (see "Blue Baby Syndrome"). Call your water supplier, now. Cheers, Neale.>> 
>A note here... Neale and I are certainly NOT trying to scare ("terrorize") anyone, nor are we "certified" health authorities of any sort... We are only trying to urge readers on to further awareness and possible action, to safeguard their livestock and safety. RMF<

Re: New African Knife fish not eating: MORE... & FW NO3 f' - 10/06/2009
Wow, I certainly will have to get someone to come out and check the water (we have a well and live near some farm fields...)
<A-ha!>
I went ahead and used reverse osmosis filtered water for my 50% water change (I would not dream of using the same tap water,) and the nitrate level is in the 30's! I may have to supplement the water with minerals, but at least this is bearable for now. Hopefully my problem is solved.
<One problem solved, and another created. Plain deionised water has zero buffering capacity and isn't suitable for fishkeeping (indeed, pure water is potentially harmful to fish). To each bucket of deionised water, add appropriate minerals to harden it up. You can buy ready made hardening salts (often called Rift Valley cichlid salts, as opposed to tonic salt or aquarium salt, which don't want). Or else, you can make your own. See here:
http://www.wetwebmedia.com/FWsubwebindex/fwh2oquality.htm
There's a recipe for Rift Valley cichlid salts, but use one-quarter to one-half the amount listed, since you want soft to moderately hard water for these fish; pH 7-7.5, 10-15 degrees dH would be ideal.>
Thanks again Neale!
<My pleasure.>
-Stephanie
<Cheers, Neale.>

clown knife questions, fdg.   9/26/09
Hey first time asker long time reader... love your site
<Great!>
I just bought a clown knife. and a love it to death best fish I've ever bought. However a live in a small rural town and the idiot at the local pet store didn't even know what kind of fish this is and therefore a cant trust anything he told me.
<Indeed.>
I have only seen him eat a few times and a keep him with 3 tinfoil barbs which can sometimes eat live foods but a don't know if he is eating at all except the few I've seen him gobble up.
<Clown Knives are fairly omnivorous. Excellent "starter" foods are earthworms, what Americans call nightcrawlers I believe. They're extremely nutritious, and their wriggling about gets most Knifefish interested *very* quickly.>
I searched a bit online about feeding a know they like live foods and frozen/freeze dried foods but when feeding him live foods how many should a put in there?
<The best thing is not to use live foods at all.>
he is about 3-4in long and they sell 10-12 feeders for a dollar at the local idiot pet shop...(this guy has me all confused)
<Do not use feeder fish, period. The reasons why have been discussed many times here at WWM, but to summarise, there are four issues. The first is disease. Any cheap feeder fish has a high probability of carrying disease. If they're selling ten fish to the dollar, just how carefully do you think they care for them? Secondly, there's nutrition. Minnows and carps (including Goldfish) contain a lot of fat, and this is known to cause problems to captive fish. I know of at least two detailed studies on aquarium fish mortality where the people dissecting fish that had died prematurely noted the fish had much more fat around their internal organs than wild fish of the same species. Minnows and carps also contain thiaminase, which destroys vitamin B1, and over time, causes very serious harm to the fish. Thirdly, there's aggression. Fish that eat live feeder fish become more aggressive, and since Clown Fish can be psychotic at the best of times, this is not something you want to encourage. Finally, there's practicality. Live feeders are expensive, and once a predator becomes used to them, it may not accept other foods, limiting your range of options.>
Do a just put all the feeders in there at the same time or just buy a bowl or something and keep em in that for a few days and just put a few in? will he over eat? will the Tinfoils eat them all?
<You don't use feeders at all, ever. There is absolutely no up-side to using feeders and lots and lots of negatives. Unfortunately, too many pet stores in the US sell feeders, prolonging this myth that predatory fish need them. Here in the UK feeder fish aren't sold at all, and no-one has any trouble keeping predatory fish. Me? I've trained mine to be hand-fed. I use long steel forceps, dangle bits of lancefish or seafood in front of the predator, and enjoy the spectacle. Clown Knives will take pellets once settled, which is the IDEAL staple given how nutritionally balanced
something like Hikari Cichlid Gold is. But in the meantime, or as an adjunct to the pellets, offer wet-frozen lancefish, squid, prawns, cockles, mussels, white fish fillet. Live earthworms and river shrimps are good
foods for settling fish in. Don't be afraid to starve a Knifefish for a while: it's battle of wills, and eventually you'll win!>
Thank you so much for ANY help you can give me
<Cheers, Neale.>

African Knifefish trouble 7/19/09
Hello!!!
<Hi,>
I have a 55 gallon tank well planted with silk plants, driftwood and fake rocks for hiding places, all of my levels are doing great and my water temp, is 79.4 F. I have a private well, so since my water is not chlorinated I do not use any chemicals in any of my tanks other than 1 TBSP aquarium salt per 10 gallons.
<Why are you adding aquarium salt? Most freshwater fish don't appreciate this. It's "old school" fishkeeping, back from the days before proper filters and so on. So unless you're keeping fish that need brackish water, don't add salt.>
I have had this aquarium for about one year. I have a couple dwarf gouramis, a gold Gourami, a couple small Bala sharks, 2 rainbow sharks, a red-tail shark, 2 Plecos, and a handful of assorted Corydoras.
<Well, none of these need salty water! What they want is something between pH 6 to 8, 5-20 degrees dH. Provided your well water falls somewhere in that range, and the water chemistry is reasonably stable, salt is redundant.>
I recently added a African Knifefish (Xenomystus nigri). I had never seen this fish before and fell in love with him immediately.
<Hmm... a nice fish in many ways, but predatory, and rather big when full grown.>
I had no trouble with him at all; I feed an assortment of flake, bottom-feeder shrimp pellets and I feed a mixture of brine shrimp and bloodworms at night, right before I shut the lights off. I loved him so much I went out and bought two more three days after I bought the first one ( I know now, from reading your site that that is WAY to crowded for three knife fish).
<They're only gregarious when young; adults are somewhat territorial, so it isn't smart to overcrowd them, and there's certainly no need to keep more than one unless you want to (and have the space).>
That was 2 days ago. As of last night all three were fine; they ate well and were very active last night and yesterday during the day, I read on your site that these fish like to hide and are shy but mine were always out in the open, and they were vey beautiful.
<Good! Shyness often depends on the aquarium: if there's shade and the tankmates are peaceful, even shy fish can be outgoing.>
This afternoon when I left my house all three were fine; when I came home all three were dying, and now, at 3:51 am they have all perished.
<Oh dear! Did you do a water chemistry or water quality test?>
I have three tanks and all of my fish are healthy. I buy all of my fish at the same store and have never had any problems with disease. I had all of the same fish for years and didn't have to buy any at all but I have been changing tanks around recently and gave my son one of my 40 gallon tanks to take to his dad's and I sent a bunch of fish with it, so I have been slowly increasing my livestock. After reading your site I suspect the reason my fish died is because of aquarium salt?
<Certainly won't be helping, but at the dose you're using, can't see that it would harm your fish.>
I cannot think of any reason for these fish to have died other that that.
I change >50 water weekly and use activated carbon power filter that cycles 500 gal/hour.
<The filter turnover rate is good, and while carbon is pretty useless, provided most of the filter is given over the biological filter media, this filter should keep the water nice and clean. Now, changing more than 50% of the water at a time is dangerous, unless you're very sure water chemistry remains constant. Exposing fish to sudden changes in pH, hardness, and even temperature can cause problems. You also don't use dechlorinator, and while your well water might not have chlorine in it, there may be other things, like copper from the pipes, that could be causing problems.>
I just don't know what I did to cause the demise of these fish and I feel horrible!. I would like to get another African Knifefish but not until I know what killed these ones.
<Knifefish are generally quite hardy, but they are intolerant of copper (including copper-based medications) and do require fairly good water quality at all times; 0 ammonia, 0 nitrite; and pH and hardness levels stably within the range mentioned above. Don't use water from a domestic water softener, either!>
Please Help!!
<Would need some data on water quality (at least, nitrite) and water
chemistry (at least, pH) before I could hazard a guess.>
Lana
<Very difficult to know what happened here. Would review environmental conditions, ensure that there's nothing stressful in the system (salt, copper, etc.), and wait a week or two to make sure the tank otherwise remained happy. If things looked good by then, and the pet store hadn't lost any fish, you might gamble on another specimen and see how it goes; you could always add a couple more down the line. Cheers, Neale.>

Clown Knife Fish; sys., fdg.   7/16/09 Hello, <Hi,> We recently bought a used 39 gallon bow front tank that was listed on a local auction website. The ad stated it came with a 9in clown knife fish and a 8inch needle fish. <You understand this tank is far too small for Chitala species Knifefish, and barely adequate for Needlefish (Xenentodon cancila)? This latter species is gregarious and tends to be very nervous when kept singly, and I can't imagine a worse tankmate than something as potentially aggressive as a Clown Knife.> I did some Googling since I had never heard of these fish, and decided I only wanted the tank, but would take the fish too since they came with the tank and then give them away. <Hmm...> When we picked up the tank the lady had already drained most of the water out of the tank. We brought a Styrofoam cooler for the fish. She filled that up and caught the fish and put them in. We left some water in the bottom of the tank We have had other fish tanks so I know I wanted to keep as much of their own water as possible. <Actually, the whole water thing is a bit of a red herring; provided fish are acclimated across, say, an hour to different water conditions, it's a good idea *not* to introduce water from an old tank into a new tank. The water fish are shipped in is laden with ammonia for obvious reasons, and it's also a good way for parasites to get from one tank to another.> We went to the store and bought 35 gallons of steamed distilled water. <Why? Do understand distilled (or RO, or de-ionised) water is dangerously toxic to fish if used raw. It must always be mixed with something else to add minerals to the water. A 50/50 mix of hard tap water and RO water works very well, but otherwise, plain vanilla tap water is always better than too much RO water.> We put that all in the tank and put the filter back on it, which we did not clean nor change the filter so we could try and keep much of the beneficial bacteria since we didn't have the means to cycle completely first. We put the heater in and warmed it up to around 75 degrees. We had also bought some feeder gold fish from Wal-Mart (bad place, I know but when it's 10pm you are left with little choice), which we put in while it was warming up. <None of these fish should be fed Goldfish; that is, not unless you want them to get sick. Please read: http://www.wetwebmedia.com/fwsubwebindex/fdgfdrartneale.htm http://www.wetwebmedia.com/ca/volume_6/volume_6_1/thiaminase.htm There are no, zero, zip, nada reasons why Goldfish or Minnows are worth using; some folks think they are, but they're ignorant. Goldfish and Minnows contain high quantities of fat and thiaminase, and over time, these WILL make your fish ill: http://www.wetwebmedia.com/goldfshfd.htm Neither Clown Knives nor Needlefish need these foods, and both, with care and patience, can be weaned onto appropriate invertebrate or wet-frozen foods. River shrimps, earthworms and small crickets are a good starting place, but with time try wet-frozen lancefish, cockle, strips of squid, prawns, etc. Variety is important, since some foods are nutritious in some ways but deficient in others (mussels and prawns contain thiaminase for example, so are good now and again, but not as a staple.> We put the clown and the needle fish in the tank, and the clown spotted (or sensed) the goldfish right away and started hunting, which I felt was a good sign. <Hmm...> I noticed right away upon putting the clown in there that he was entirely too big for this tank and we need to get him a bigger tank ASAP. Oh did I forgot to mention once my husband saw him, he wanted to keep it. <I see.> There was 11 feeders in there, the clown ate 2 with in an hour of being put in the tank and us sitting there watching him. The needle fish ate 2. <May I ask how you checked the Feeders didn't contain gut parasites, worms, etc? Forgive me if you're a microbiologist with access to a microscope and appropriate dissection tools for random sampling. You didn't check? Ah, that's my point! How well maintained do you imagine Goldfish are that are cheap enough to sell ten for the dollar? Cooped up a thousand per 50 gallon tank? I think you see where I'm coming from here: Feeder Goldfish are hands-down the worst possible way to feed a predatory fish. The risk of one Feeder might not be too great, but ten, a hundred... over the weeks and months the risk goes from negligible to very serious.> We got the tank on Saturday, all the feeders that were in there were gone by Monday night. Tuesday I went to the local fish store and started picking their brains about the fish and what I could do to make it more comfortable. I bought some more feeders from them, goldfish for the clown and Rosey red minnows for the needle. <Argh!> Each morning I have woke up and had to fish a goldfish out who's guts were hanging out. Yesterday I put in 6 feeder and had to fish out one this morning. I decided not to put any more in till tonight and would only put 2 in for each of them. I originally thought it was the needle fish trying to eat a bigger fish than he could handle, but tonight I fed them and my husband was watching them (he is very intrigued by the hunt), <Biting my tongue here...> and he saw the clown get one, then took it over to his corner and spit it out. The body that was left floating fit the same description as the others I have been fishing out in the mornings. I thought well maybe they are too big. The clown went after another and got it. My husband originally thought he swallowed it, but looked again and nope he spit this one out too. I just went and fished those two carcasses out of there. Currently there is one Rosey red and one gold fish left, and the gold fish is swimming but appears to have been swiped at by either the needle fish or attempted to be eaten by the clown. <I see.> Can you give me some incite as to why he would be spitting them out? <Got good sense?> I am going to take my water to be tested hopefully tomorrow. I did buy some Amquel Plus to put in the tank to get rid of nitrates and ammonia. <Amquel Plus removes ammonia from tap water; it has no impact at all on the ammonia produced by your fish, and certainly isn't a solution to poor water quality.> Should I be putting in aquarium salt in too? <Whatever for?> I bought 2 pieces of slate to try and give the clown a bigger place to hide, am afraid to stick my hands in the tank long enough to place them securely. He seems to get stressed if I turn the hood lights on, which I rarely do because I know they like the dark. Will this lack of light bother the needle fish? <No.> He seems to be doing well, I just wonder where the heck he puts two fish in his gut!! haha. While I still don't want either of these fish, my husband does and we will be setting up our 125 gal tank as soon as we can locate it (it's in storage somewhere)... <I see.> I hope I gave enough information <No really; I need the following, at minimum: temperature, filtration rate (or at least make/model), nitrite, and pH.> I will include the picture that was listed in the ad I bought it from. Oh and I forgot to mention this has sand in it instead of gravel, is that OK? <Fine so long as it isn't too deep; an inch, tops, unless you have plants with roots.> There is also some black stuff, which the guy at the fish store told me it could be black and white sand mixed, but he wasn't for sure with out seeing it. <Looks like black sand to me.> Also, since the clown is so big, I took out almost all the decorations, I felt it was too much for him to have to try and navigate through, the clay pot is in there but he is too tall to fit in there, he hides behind the rock thing in the corner by the filter (which is now on the other side of the tank) I included a couple pictures of the clown also, hope they aren't to big. If you have any other suggestions I am all ears, as I am completely new to these kind of fish and you have to seem quite a bit of knowledge on them. Thanks, Carrie <Neither Needlefish nor Clown Knives are "easy", and I suspect you're going to find these fish very challenging. Your first job is weaning them onto a proper diet; you simply cannot carry on with the Goldfish, so the fact they're not eating them isn't a problem. Let them starve for 3-4 days, and then offer something else, perhaps earthworms or mealworms. I find metal or plastic forceps really useful for offering such foods without disturbing predatory fish; for some reason, they'll ignore the forceps while being freaked out by fingertips. You could also try frozen lancefish, holding them in the current with the forceps and wiggling them enticingly. Needlefish go for "flashes" of silver, and once they bite, they tend to consume whatever they've caught. Clown Knives aren't too fussy, and some specimens even take pellets, but it's often a trial of wills at first. Offer as many different things as you can, including white fish and seafood from the kitchen whenever you have some. See what he goes for! I happened to have an article in the June 2009 issue of TFH Magazine on these fish, so if your local library has a subscription, you might want to stop by and have a read. Do bear in mind Clowns will routinely reach 75 cm/30 inches length under aquarium conditions, and depending on the species can get much bigger than that. Cheers, Neale.>

Re: Clown Knife Fish - 7/16/09 Hello again, Thanks for your reply. I do feel a bit disturbed by your reply, but you gave some really good information overall, so I can get over being disturbed. <Very good.> Please understand that we got this tank and went on information given to us by the previous owner. We are feeding it what she told us, if nothing else we saved these guys by taking them out of an unknowledgeable home and brought them here, where we at least try to find all the information we will need for them to be the best fish they can be. <Indeed so.> After reading many sites I am fully aware of how big they can get and how much work they are, which is why I don't want to keep the clown. My husband wants to keep it and although I am the one who will likely end up taking care of it, if he wants it and we can house it then so be it. Like I said we have a 125 we are going to move it to. I would like to have that set up and properly cycled before moving it. Yes, I know even a 125 is too small. My husband is more than willing to get a 300gal tank. We have already started researching on where to get one of these monsters from. <An expensive proposition from new, but used tanks are rather less expensive.> The needle and the clown seem to be ok living with each other. <For now. The problem is that (male?) Chitala can become very aggressive. What is known about their habits in the wild suggests males defend nests, in some cases so aggressively they attack humans in the water.> The clown sticks to the bottom and the needle to the top, but I do understand what you are saying about them not being good tank mates, when we move the clown the needle will not go with it. Again this is how they came, so we were going with very bad information. <Fair enough.> I had no idea the raw water would be bad for the fish... point noted and taken seriously, I will never make that mistake again, I thought I was doing good <Raw, de-ionised water is indeed very, very bad.> I will not feed them for 3-4 days. Can I try thawed frozen shrimp that comes in a bag at the grocery store or I thought I read in another reply they said shrimp off the ice in the coolers in the store. <Yes, once or twice a week, shrimps are fine. But they MUST be a minority component of their diet. It's steadily becoming clearer that thiaminase is a major health problem, so read through that article linked last time, and draw up a shopping list of foods that are thiaminase-free.> I will follow your tips to get them off the goldfish and rosey reds. Can I use earthworms that you buy at a tackle store for fishing with? <Yes.> I feel there is no need to be rude here, I got these fish with the tank. They were obviously being mistreated by their previous owner, at least I have the sense to research more about them, so I can try and take care of the right way. I did not inspect any fish for any parasites or anything. <That's my point; we aquarists can't, hence the need to be careful and use safe food. If I'm being forceful in my argument here, it's because an awful lot of aquarists, especially in the US, seem to use feeder fish.> I didn’t know better and well you can change the past only learn from our mistakes and try to find better ways in the future, which is what I am doing emailing you. <Point taken.> I had no idea, the guy at the fish store suggested I put it in so I did. <Do always remember the guy in the fish store is selling you stuff; I'm here volunteering to answer e-mails because I won't people to have more success keeping their fish.> I don’t know what [the addition of salt] for. All I know is the previous owner told me she did it. I am trying to get all the “proper” information here, which is why I am asking questions. A simple “no there is no need” would have sufficed here. <As you prefer.> The filter is a Tetra-O FS 20-40, again this is what came with the tank, I am not claiming that it is a good enough filter. <Hmm... not familiar with this. Is this the FS AquaTech 20-40, which pumps 170 gallons per hour? Check the "gph" rating on the filter. For your big fish you need at least 6 times the volume of the tank in turnover or not. So for a 40 gallon tank you'd want 6 x 40 = 240 gallons per hour. For a 125 gallon tank, 4 x 125 = 500 gallons per hour, and so on.> I don't know if it is or not. I don't know a lot o the care of these fish at all and that’s why I am coming to you. <While we serve it "straight up", you are getting good information here.> I will take the information you have given to me and try to do my best. I actually have not found a whole lot of information on the needle fish, can you recommend some good reading on those? <There's a primer here, about halfway down: http://www.wetwebmedia.com/FWSubWebIndex/belonids.htm They're fairly widely kept by advanced aquarists. Do search by their Latin name, Xenentodon cancila.> Thanks, Carrie <Cheers, Neale.>

Black clown knife with pop eyes?   2/25/09
Hi!
Hopefully you can help me with a problem..within the last week. my black clown knife's eyes have been bulging and they are getting worse. I have done a 50% water change. but the BCK is now swimming by the top and I want
to help him. but don't know what meds to give him. Can you help?
Thanks!
Karen
<Hello Karen. With Popeye, there are usually two causes. If there's just one eye popped, it's likely physical damage or aggression, so you need to look at things from that angle, checking the tank is big enough for the fish, doesn't contain aggressive tankmates, and so on. If both eyes show a similar degree of swelling, it's usually an environmental issue, in which case you need to review water quality and water chemistry stability. Clowns are big, messy fish and need extremely generous filtration to stay in good health. For an adult specimen (at least 60 cm/24 inches in length) you'd be looking at a tank around 750+ litres (200+ gallons) in size and equipped with a filter rated at 8-10 times the volume of the tank in turnover per hour. 50% weekly water changes would surely be essential. I'm mentioning
all this because unless the environment is fixed, the eyes won't heal. So far as treatment goes, an antibiotic like Maracyn coupled with Epsom salt in the water at 1-3 teaspoons per gallon should do the trick.
http://www.wetwebmedia.com/popeyefaqs.htm
Cheers, Neale.>
Thank you for your help! :0) I do appreciate it! :0)
-Karen
<Happy to help. Good luck, Neale.>

Re: Xanthichthys auromarginatus/freshwater killer... feeding and Notopterus comp. – 2/4/09
Thank you for the email,
After sending it, i realized that blue throat triggers eat the smaller foods like mysis shrimp and brine shrimp. (are those the same thing?).
<Nope>
Anyways i put some frozen brine shrimp in (enriched, im getting some Kent Zoë today) and he swam around eating it.
<Ah good>
To answer your question the two eels are echidna nebulosa and Gymnothorax richardsonii. they are small right now, at about eight inches, and i vary their diet with frozen silversides, live mussels, clams, and crabs, and frozen or raw crabs and frozen or raw shrimp.
<Sounds good>
On the freshwater topic, I was just curious if a protein skimmer would work on a freshwater tank, or if one would need a skimmer.
<Mmm, not really and no...>
I am not planning to ad one or anything, i am just curious. Also, when the clown knife gets bigger, would it be wise to separate him from the king tiger Pleco, and the black ghost knife?
<Yes>
Do you think the tire track eel and the silver dollars will be safe in the long run too or is it best to separate them when he gets to a certain length?
<Could be inhaled with a big "Whomp" some evening...>
thanks for all the info,
will
<Welcome. BobF>

African Knifefish Problem.. it died. - 7/2/08
Hello,
Recently I had bought two more fish to add to my 75 gallon tank; a Senegal Bichir and an African Knifefish, a Domino Synodontis and another Senegal Bichir were already in the tank.
The first night the African Knifefish was added I had noticed a white spot on his side that looked almost like a bite.
<Likely what it was. Whilst the fish listed here can work acceptable in robust community tanks, both Polypterus and Xenomystus have the potential to be aggressively predatory, particularly if they are hungry. Neither has good eyesight, and both hunt primarily by smell and using their lateral line. Or put another way, they sometimes bite whatever comes in range!>
The Bichirs I have are very calm and peaceful and didn't mind the Knifefish, actually when we got them from That Fish Place they were in the same tank together. The catfish rarely comes out of his hiding spot and never bothers any of the other fish, so I do not know how he would have gotten a bite.
<Synodontis do tend to avoid being bothered by other fish. For one thing they are quite heavily armoured (and armed). Synodontis also have a few behavioural features that help. They are, as you note, very retiring. They also tend to attack things that annoy them. Finally, they make "clicking" sounds that disturb other fish, and seem to work as quite a useful anti-predation mechanism (in Africa, Synodontis are known as Squeakers).>
Over the next day that spot had gotten larger, it didn't even seem to bother him though. He was eating and very active. That night the spot had spread to an off-black color and began to stretch across the other side of his body.
<When wounds get larger, even if they don't seem to "bother" the fish, you need to do two things: [a] establish the cause; and [b] treat preemptively for Finrot and Fungus.>
I did a 20% water change and set the temperature to 80 degrees.
Yesterday he seemed to be doing fine, even the spot looked like it was shrinking.
This morning when I turned on the light he was on the bottom of the tank upside down. I'm just wondering what could have happened to my Knifefish.
<Quite likely a secondary infection, perhaps exacerbated by stress or starvation, depending on how well settled and how well fed the fish might have been. Juvenile Xenomystus are somewhat gregarious, and the singleton might have been bullied by the Polypterus senegalus. That said, P. senegalus is generally very well behaved, particularly when compared to other members of its genus, so to be honest I'd be surprised if this combination of species didn't work in a tank of decent size and adequate numbers of hiding places. I'd review water quality and water chemistry simply as a matter of course; whilst Polypterus and to some extend Synodontis are "hardy" in the sense of being easy to keep, Xenomystus (like other Knifefish) are FAR from hardy in aquaria, and can be killed by ammonia/nitrite, rapid pH changes, many fish medications such as those containing copper and formalin. So there's a range of things to review there.>
Any information at all would be wonderful, thanks.
-Carly
<Cheers, Neale.>

African Knifefish with Elephant Nose... Ost. comp.     01/13/2008 I've read conflicting information in various media concerning putting African Knifefish with Elephant Nose fish. <Indeed?> I'm moving my 7" African Knife into his own 55 gal tomorrow and would like to know if I can put my two 5" Elephant Nose with him. <Possibly, but Elephantnoses do get a bit territorial, so make sure it has lots of hiding places. Xenomystus nigri isn't one of the Knifefishes that generates an electric field, but it is apparently sensitive to them. So while I doubt the Elephantnose will make a bee-line for the Knifefishes in the same way it does other electrogenic fishes, the Knifefishes might get annoyed by the electric field from the Elephantnose, and that could lead to tensions.> I know both fish have weak electrical fields. <Xenomystus nigri does not generate an electric field. Appearances aside, it belongs to the non-electrogenic Notopteridae Knifefishes, a different group to the electrogenic Gymnarchidae and Gymnotiformes, both of which contain true electrogenic species.> Several sources say you can mix Elephant Nose with African Knifefish but *not to mix them with Black Ghost Knifefish. A bit confusing because they don't say WHY. Temperament perhaps? <Black Ghosts -- Apteronotous albifrons -- are members of the electrogenic Gymnotiformes group, and likely when Elephantnoses and Gymnotiformes are mixed, the two varieties of fish annoy each other with their electric fields.> The 2 Elephant Nose bump into each other but I've not seen any aggressive behavior in the 2 months I've had them, they seem to get along well and were bought together from the same tank. <In theory, Elephantnoses are schooling fish, but in captivity they often don't get along. The reasons aren't clear for this.> All 3 fish are great eaters but I'd like to keep them separate from my other fish because I'm afraid they just wouldn't be able to compete for food in other tanks. <Agreed, though provided Elephantnoses are mixed with species that never take food from the bottom of the tank, they can be placed in communities. Hatchetfish, halfbeaks, Danios, African Butterflies and so on would work.> Would it be a reasonable solution to put them together? There will also be a 1 1/2" Raphael Catfish but no other fish. <Certainly worth a shot. I tend to recommend against mixing catfish/loaches and Elephantnoses because of problems with feeding. But if your fish are feeding well already, then maybe you'll be fine.> Thank you for your time, options & your dedication. Sincerely, Mitzi <No problems, and happy to help. Neale.> Re: African Knifefish with Elephant Nose  01/14/2008 I'm going to go look (online 1st) for "The Diversity Of Fishes" and snatch up the 1st copy I find, thank you! You can't put a price on a good book that you can refer back to for many years, I love books. It fascinates me that if we give a fish what IT needs (physically, psychologically & diet-wise) that the other aspects fall together. <Hi Mitzi. Yes indeed... one of the nice things about keeping fish (compared with, say, dogs) is that it's relatively easy to create an environment so natural the fish will complete its entire, natural life cycle in captivity including social interactions, courtship, breeding, and brood care. Dogs, by contrast, are largely limited to being pets, and rarely get to interact fully with other dogs, let alone organise themselves socially.> Common sense should tell someone Elephantnose don't need any bottom feeding completion. The fish shop told me to put them with Loaches and feed only brine shrimp, I just roll my eyes at them most the time. <All too common. Most stores see them as oddball "scavengers", which they're SO NOT!> These 2 will eat just about anything. I had to get creative but I figured out that if I cut stringy chunks of any kind of meat or insect they'll devour it. <Try putting in a small ball made of aluminum foil; supposedly Elephantnoses find these "toys" fascinating!> All my tanks have zucchini or squash in them and they even mash their funny noses into that. I haven't figured out if they're eating or not yet-but it's sure fun to watch them! <Not sure if they're eating it, but perhaps. They do hunt mostly by olfaction, and only secondarily using electric field detection. Hence they "touch" interesting things with that chin barbel to taste it.> It makes me wonder if they can communicate somehow. <Yes. Communication in Elephantnoses has been much studied and is known to be extremely complex. Essentially, dominant individuals "monopolise" the best frequency, and lower status individuals have to use less desirable frequencies. Within the group, there's constant jockeying as fish try to use the best frequency (i.e., the one that offers best navigation resolution). Presumably, they also use electric signals to convey things like sex and willingness to mate.> One will find food and 1/2 a second later the other one will come shooting as fast as he can from the other end of the tank. Just like chickens. <Hah!> I can't wait to find that book-thank you so much! Mitzi <There's quite a big chapter on electricity in fishes; it is a unique sense that fish have but no other vertebrate (something to remind those annoying "warm, fluffy animal" chauvinists! Enjoy, Neale.> Re: African Knifefish with Elephant Nose  01/14/2008 Food for thought here. There was much you told me that I honestly didn't know. I don't know where else I'd have found such specific information (which is why I pick your brain often). I wish I had access to some sort of a "fish library" like the medical library we have. I'd be in heaven. <Hi Mitzi. If there's one book I'd recommend for anyone interested in fish beyond merely keeping them alive in a glass box, that book would be 'The Diversity of Fishes' but Helfman et al. It's a university-level text book, but so well written, and with so many diagrams and photos, that I think anyone with even a mild interest in how fish work and what they do will find it a fascinating read. Not a cheap book (I think I spent about £50 on my copy ten years ago) but should be accessible through libraries or used book stores if you don't want to pony up for the new edition. But trust me, once you've taken a peak, you'll want your own copy... it's that good!> I did move the African Knifefish & his little Raphael Catfish yesterday as planned but did *not put the 2 Elephant Nose in there, it didn't feel right to do so because the Elephant Nose are such busy bodies. <Elephantnoses are exceptional fish in many ways, and great fun once you understand their needs. They are among the very few fish for which scientifically accepted "play behaviour" has ever been observed, implying a level of intelligence well above what we normally associate with fish.> I didn't want Wendell the Knifefish to be stressed with all that activity. After reading what you had to say I'm glad I held off. <Cool.> The Elephant Nose have been in a 3 ft tank with 10 Hatchets and I guess they'll stay there until the aquarium fairy brings me a bigger tank for them. <Sounds as if he's happy. You seem to have figured out that elephantnoses do best with surface-dwellers. Good call.> Thank you, Neale. You've no idea how much I appreciate you. <Not a problem.> Mitzi <Cheers, Neale.> Re: African Knifefish with Elephant Nose  01/14/2008 So much I didn't know about the Elephantnose-even after all I thought I'd read. <Always the way!> I found the book and ordered it on Amazon.com. I'm so excited :-)) My birthday is Jan 15th so it's a birthday present to myself, I can't wait to get it! <Hope you will enjoy.> I actually do understand the interactions of dogs, to a certain extent anyway as mine are all spayed or neutered. Dogs were my "1st love" as far back as I remember. People seldom understand why I 'want' a dozen dogs in the house but then they don't understand my fascination with a dozen aquariums either. I see & understand the interactions between the dogs, I can tell at a glance what each dog is portraying to another, why they're doing it and how to either stop or encourage the behavior. The dogs know the 'leader' is the short blonde lady with the aquarium hose-ha! <You "get it" -- Dogs are happier when kept in groups of their own kind, not just with people. At the very least, it's so much nicer for a dog when you take it on walks with someone else's dogs too, so that they can make a little "pack" and go do their thing, instead of always following the Two Legs about.> Sorry to take up your time, but I learn so much from you and maybe what you write will help someone else with these same kind of fish. <Who knows!> Thank you!! Mitzi PS I'll try the aluminum foil with the Elephantnoses. It'll give me and the Hatchet fish both something to watch :-) <Let me know what happens. Have read this, but never seen it. Cheers, Neale.>

African knife fish (Xenomystus nigri) fish/system compatibility question  8/4/07
<Hi Matt, Pufferpunk here>
I have read much of your site (actually just about everything in your freshwater fish section and half of the planted aquarium section) in my leisure time at work and I could not find a definitive answer to my query.
<I wish I had that much leisure time at work!>
I currently have a 120 gallon tank with seven 4-5" silver dollars, an 18" common Pleco and 6-8 Cory catfish (plus about 200 plus snails of various species). The tank is well established, (ammonia 0, nitrites 0, nitrates... too high, I wont be getting the knifefish unless I can controllably get my nitrates to under 20ppm) has a variety of floating plants such as anacharis, Watersprite, and duckweed (which my silver dollars regularly nibble) and there is a large piece of driftwood which keeps the tank at a steady 6.6 - 6.8 pH.
<I would suggest huge weekly water changes but I think that may cause the pH to fluctuate too much. Maybe a large sump/veggie filter is in order here. Definitely no adding of new inhabitants now.>
I have built a PVC pipe condo with 2 inch diameter pipes that are 12 inches long each, into a pyramid type structure consisting of 15 tubes held together by Gorilla glue. I would like to buy between 5 and 7 African knifes to put in here. I have had one before (a while back in a different smaller tank) which only ate frozen food and instantly spit out flake food when tasted. I have read that these knife fish are somewhat sociable, not to the point of schooling but in that they do hang out together and when being fed dry foods, they would be more likely to consume it due to competition. Is this a sound theory that is tried and true?
<I'm not sure where you got that info. According to Baensch: "Difficult, larger animals are solitary and aggressive towards other Xenomystus nigri". In other words, 1 per tank. I also think topping out at nearly 1 foot, you are dreaming of way too many knives in your tank.>
Is it fish dependant? Or will it just take some time to wean them off but in the end, most should be used to flake food? (with the bi weekly frozen food treat of course).
<Although fed a variety of foods (my knife lives with 7 discus) I have never seen my knife move from his hiding spot to eat anything on there than live worms. Although I read the fish can get used to strips of raw meat.>
And also, is the size of my tank large enough for such a mixture?
<I'd say that one of this species would work well with your set up.>
Right now, the silver dollars mostly stay at the middle level and the Corys are also at the bottom and never in the PVC pipe condo, so I figured that maybe this would be suitable. My last question being, will the knife fish get along when they get older or will they become antagonistic like other knife fish?
<No>
I just bought a new light which has moonlight LED's so now I can actually observe the knife fish swimming around without sitting in the dark and holding a small flashlight on the tank, so I am rather excited for this purchase.
<Cool!>
The only things holding me back are my high nitrates (about 120ppm +/- 40ppm) and fish compatibility.
<That IS high!>
I only hope that my new aquatic plants (with their new 260watt full spectrum fluorescents and actinic bulbs, as opposed to the old 60 watt mercury bulb) and removal of my giant canister filter (Fluval FX5 aka nitrate factory) will be enough to reduce the nitrates in the coming weeks. Thank you very much for your help and for having such a detailed site. I myself work as a chemist in a machine coolant company so I often read many things which actually pertain to my job, which is always a plus. Thanks again.
<Look into a large veggie filter for that tank.
http://www.thekrib.com/Filters/plant.html#8
Please note that when purchasing, most of these fish that are bought as juveniles do not survive the first month. Enjoy your knife! ~PP>
Matt, NJ

Clown Knife Fish Non-Live Food Training – 06/28/07
Hello, Your website is great! Unfortunately I could not find anything about training a Clown Knife Fish to eat non-live food. I've tried even warming krill/shrimp, I've tried Shrimp Pellets, Freeze dried Bloodworms, and Flakes. My 6" clowns just don't eat it. I have to revert to Live Ghost Shrimp, but I do not want too. Please help me find a way to train the Clown Knife to eat other prepared foods? Step by Step, please. As you know, Feeding time for these guys is only at night when the lights are off. Hope you can help? Thanks
<Greetings. Training Knifefish to accept dead food follows the same pattern as with any other opportunistic carnivore -- patience and a little starvation! As you realise, many people keep Knifefish by feeding them goldfish and minnows. This is very dangerous in the long term because of the risk of introducing parasites and the poor nutritional value (high fat and thiaminase content) of goldfish and minnows. So well done on doing the responsible, sensible thing by weaning your Knifefish onto safe alternatives. Small Knifefish are fond of (wet) frozen bloodworms, i.e., the kind you keep in the freezer. I have yet, in 20+ years of keeping fish, to find anything that likes freeze dried bloodworms or brine shrimp. I know people use them, but I've never had any luck with them. So get the wet frozen kind. These smell yummy and even difficult fish seem to accept them readily. If you train the baby Knifefish to take frozen foods, feeding the adults becomes very easy. Larger Knifefish in the wild eat fish, large insects, and crustaceans, so these are the things to concentrate on. One of the best ways to use frozen whitebait (or any other small, silvery fish) is to defrost it and then throw it into the current of water coming out of the filter. The flash of silver mimics the movement of small fish, and predatory fish will usually strike at the flash, and eat the food. I have personally found small pieces of oily fish (such as salmon or herring) extremely good for tempting predatory fish, presumably because of the smell, but be warned that oily fish *heavily* pollutes the aquarium and you will need to do a big (50%) water change afterwards. As well as fish, crustaceans like unshelled prawns and crayfish are excellent foods for adult Knifefish. If all else fails, alternate live foods, such as earthworms, mealworms, and crickets can also be used. Once the Knifefish learns to accept a variety of foods, tempting them onto floating pellets is not difficult. It helps if they share a tank with other fish that feed from the surface, like Tinfoil Barbs or Giant Gouramis. The Knifefish will see where the food is coming from, and take the floating pellets. Obviously, Knifefish are big and potentially aggressive, so don't mix with smaller fish or anything likely to pick a fight (like cichlids). Cheers, Neale>

Re: Clown Knife Fish Non-Live Food Training – 06/29/07
 You guys are great! Thank you Neale for the information.
<You're welcome. If you love Knifefish, keep an eye out for a book called "Jurassic Fishes" published by TFH. It's a beautiful book, sadly out of print, but filled with the loveliest photos of Knifefish as well as other "monsters" like Arowana and gar. One of my favourite books! Neale.>

Feeding a Clown Knife
Hello guy's I just have a little question to ask.
I have a clown knife. it's probably six or seven months old (guessing). He has been eating Rosie's and small gold fish on a regular basis. He can eat about
two dozen in a couple of days. My question is this, would it hurt him to eat earthworms? He's only had two, but he loves them. Gobbled one up before it hit the bottom of the tank. Just wanting to know so that I don't hurt him.
>> No, earthworms are fine, he will likely eat some frozen foods also, try him on frozen Krill, smelts or Mysis! Good Luck, Oliver

Clown Knife Vision, Navigation - 09/02/2005
Do Clown Knifefish have good eyesight?  
<Nope, pretty crappy, actually.>
Also, do they possess and use the electrical organ for navigation like Black Ghost Knifefish and Elephant Noses?  
<These are actually very different from the clown knife....  The clown likely uses scent more than anything for finding food and such.  Please see here for more:  http://www.wetwebmedia.com/FWSubWebIndex/osteoglossiforms.htm .>
Thanks,  Kristen :)
<Sure thing.  Wishing you well,  -Sabrina>

Clown Knife, Cory Cat - 08/16/2005
Greetings Bob,
<Hi, Richard; Sabrina here, this morning!>
This morning I noticed my clown knife had something in it's mouth and it turned out to be a Cory cat.  
<Yikes!>
I knew that the clown knife ate live fish but I didn't think it would until it was much bigger.   My knife is about 6-7 inches long right now.  
<That's plenty big for any knife to start eating small fish....  These are very efficient predators.>
The Cory seems to be stuck in his mouth.  
<Not good....  Chances are, he spread his dorsal and pectoral fins to prevent being eaten.  I suppose it worked, sort of....>
It has been in his mouth now for a few hours.  Is this normal?
<No, and yes.  It's a normal reaction for the Cory to prevent himself being eaten, and it's normal for a clown knife to try to eat smaller fishes....  If the Cory is dead, and the knife is in obvious, extreme distress, I would try removing the Cory's pectoral fins with thin, VERY sharp scissors, then pull it out - GENTLY - or have a vet do so, if you've got a vet who would.  If the Cory is alive, let 'em have some time to work this out.  Watch the knife very closely for a while.  This may work out fine on its own.>
This is the first time I have seen my knife eat live food.  Please advise.
<Err, this is probably obvious, but whatever the outcome of this instance, remove all smallish catfish from the knife's tank, or you'll be sure to see this happen again!>
Warm Regards,  Richard D. Warren
<Wishing you well,  -Sabrina>

Clown Knife, Cory Cat - II - 08/16/2005
Sabrina,
<Hi, Rich>
Thank you for your help.  
<Any time.>
Unfortunately my knife didn't make it.  
<I am so sorry to hear this....  So sorry for your loss; they are such beautiful, interesting fish!>
I appreciate all your help though.
<I wish I could have been of more help.  Perhaps in the future, you might look to Xenomystus nigri instead of the clown....  Though it might still have the same issue with small Corys and otos, it would stay small enough to be safe with larger Corys and other catfishes.>
Rich Warren
<Wishing you well,  -Sabrina

Clown Knife not eating 7.23.05
I have a clown knife fish and I moved him from a 45 to a 75 and know he is not eating. He was eating at least 55 Rosies and mixed with some goldfish now he goes on his hunt eats maybe one or two. Its been two weeks since I put him in the new tank. Ph and everything is fine with water. Help me please
<As long as your water parameters are in good shape I would not worry too much, make sure he has somewhere to retreat to and hide in the new tank.  He may still be getting used to his new surroundings.  I am sure he will come around. -Gage>

Clown Knifefish system 7/10/05
Hi, I have recently just purchased a Clown Knife Fish and am confused about what PH the tank should be.
<Where they live in the wild the pH ranges from 6-8, so anywhere in that range, as long as the fish is properly acclimated, will work fine> So far my tank is at 6.8 as suggested by the place of purchase, but I have been reading that other people have their tanks set at 7.0 or higher.
<6.8 will work fine>
I really enjoy having my fish and don't want anything to happen to it. I have a 55 gallon tank right now and would also like to know any suggestions you may have on a good tank mate for my clown knife fish. I would really appreciate your feedback.
<Be aware that the clown Knifefish (Chitala chitala) attains 4 feet+ in length, and will most definitely outgrow your 55.  It will eventually need a ~500+ gallon tank if you are to keep it to adulthood.  As for tankmates, anything not too aggressive, and nothing that is a fin-nipper.  If you're looking for big (for that future 500 gallon tank ^^) you could go with a 'Royal pleco'>
Sincerely,
Steve
<M. Maddox>

Clown knife problem 7/5/05
Dear Bob,
           I hate to  bother you with this, however you seem like one of the only people that might be  able to help me.  I have a clown knife, approximately 7 inches long.   He was accidentally overfed and became grotesquely bloated.  I haven't fed  him now in a month, yet the bloating has not gone down.  I spoke to the  owner of a local fish store who advised me to add salt to the water.  I  have been doing this but it doesn't seem to help.  I have never seen this  before and I am having a difficult time finding anyone who can help.  
<Mmmm, what sort of salt? I would try a level teaspoon of Epsom (Magnesium sulfate) per ten gallons of water>
    Have you ever seen or heard of this before?   If so, what should I do?  
If not, can you refer me to someone?  Thanks  again for your time.
Warmest Regards,
Janet Sanders
<Some sort of gut blockage... what were you feeding? Hopefully not goldfish... Bob Fenner>

A budding pet-fish ichthyologist, Pantodon plants, Knifefish selection  - 1/30/2006
Yes, I have... however I'm only fourteen and I don't think they'd take me.
<You might be (pleasantly) surprised here... Do speak with your parent/guardian re the time commitment, pledge to maintain your current school work, and look into arrangement of a "work permit" from your school, and ask the management to consider hiring you part time... This is how many of us "got started" in the industry... at and below your age>
I have two Big Al's, aquariums west and some Petcetera's (Canadian chain stores) nearby, though, so when I get older I will have some options. By the
way, I got the butterfly fish, I believe it is female as there are 13 rays in the caudal fin.
<Indicative in Pantodon>
It seems to have an appetite for, surprisingly, pellet food.
<Ah, good>
You'd think with that huge ramp mouth it might go after something else, but it just waits for the pellet food. She (?) won't even eat freeze
dried Tubifex or blood worms that float on the surface, and gets along great with my two new upside down cats (!!). Thank you for your valuable advice. I have moved my CAE into my 20 gallon hospital/quarantine for now because it is starting to get an appetite for my other fishes' slime coats.
<Am very glad for your close observation and action here>
I hope to give it away sometime in the near future, as it is around 4 or 5 inches, maybe 6 with the tail. By the way, I was wondering if you could give me some
advice on any floating plants for my tank?
<Sure>
I have heard that they keep the butterfly fish from jumping,
<Helps, yes>
and I only have some Cryptocorynes and Sagittaria right now. My tank is fully covered, but I do not want her hurting herself on the hood.
<Look for Ceratopteris... water sprite... my fave here>
I also checked Big Al's for knife fish while buying the African butterfly, and they carry brown knifes (Xenomystus nigri?)!
<Mmm, no... this is a Notopterid... a "Featherback Knife"... see elsewhere re S. American Knives... perhaps a search on Fishbase.org>
These apparently stay smaller, so I will look into them once I have a larger tank up and cycled. Thank you for all of your help.
-Eddy
<Welcome. Bob Fenner>

Clown Knifefish, Tiger shovelnose feeding, Toadfishes
Dear Bob and Associates,
I am a relatively experienced freshwater aquarist, but I have a little problem that I have never been able to find a solution to. I have a juvenile clown knife (Chitala chitala, 6") and a juvenile tiger shovelnose (Pseudoplatystoma fasciatum), and I am stumped as to what to feed them besides live foods (ghost shrimp and mollies/platies - never "rosy reds" or goldfish). I understand the enormous size these fish will attain, and I do not want to feed them unhealthy live fish (i.e. - goldfish) as they grow. Do any of you have experience with these fish? Since they're nocturnal, I assume that it would be best to try whatever non-live foods you suggest after lights-out in the aquarium.
<I would feed these guys glass worms, blood worms, plankton, mysis, etc. Live ghost shrimp on occasion. Pelleted foods if they will eat it. If you are going to continue with the mollies and platies you should gut load them with the above foods.>
I also have developed a huge fascination with toadfishes. I am particularly interested in the three-spine toadfish (Batrachomoeus trispinosis, commonly sold as "freshwater lionfish", though I know it's heavy-brackish to marine). Do you know of any web sites with comprehensive and DETAILED information on these fish (or toadfish in general...I have looked on fishbase.org, posted in the WetWeb forums, etc. and had no luck)? I would like to set up a "community of toadfish" fish-only marine tank, but I don't want to go into it blind.
<Unfortunately I do not have much information on these fish, I would start with a search on google.com. Have you checked http://reefcentral.com/
There is also some information at the link below
http://www.wetwebmedia.com/batrachoididae.htm
Best Regards, Gage>
Any info you could give (whenever it is convenient for you...no rush) would be greatly appreciated. Have a great day! Thanks, Matt Parkison

My new Clown Knife & Ropefish
I just purchased a Clown Knife (about 6"). I put him in a 25 gallon hex with a Rope fish and they seem to be doing fine. I've been told that both can grow quite large. Do you think they'll be ok or should I return them.
<Return them....  My clown knife grew to a length of 25 inches long! It is now living quite comfortably in a 650 gallon tank...  It was originally living in a 150 gallon tank but outgrew that!  The clown knife will reach 18 inches long in about a year and a half, this fish will NOT be able to live in a 25 gallon tank.  As for the Ropefish (Erpetoichthys calabaricus) These fish will get over 36 inches long as adults... and require a 90 gallon tank.  So, that too will not be able to live in a 25 gallon tank.  I suggest you do some research before purchasing fish, there are many fish that will do quite nicely in a little 25 gallon tank.  Many of them are just as interesting as these fish.  Trust me it's no fun having a fish that is in a tank to small for it.  These fish are sick all the time, and you have to constantly be changing the water to keep up with the waste output.  Good luck. -Magnus>

Clown Knife 
I am thinking of purchasing a Clown Knife fish and I was wondering what size of aquarium I should purchase?  I was also wondering what are common tankmates for a clown knife?
<I raised knife fish for many years, and the Clowns are some of my favorite species!  They get really (really) big, they usually stay around 2 feet long in the home aquarium. In the wild you can find these fish around 36 inches in length.  The largest one I had was just over 25 inches long and was being housed in a 150 gallon tank.  though she seems slightly cramped in there.  I would say that a 150 is the bare minimum for an adult clown knife.  I eventually moved her to a 650 gallon tank since she was so large.  As for tankmates, Clown knife fish aren't aggressive.  They don't typically pester other tankmates, unless they are very small.  The other tankmates MUST be larger than the clown knifes mouth.  If they are bite-sized fish they are gone!  My clown was over 18 inches long within the first year and a half, and at that size it could easily swallow a 3+ inch goldfish.  I kept a school of tinfoil barbs with my clown, these fish were about 8 or 9 inches total in length.  The barbs were very active and didn't seem to get in the way of the clown at all. Also in the tank was a Pleco, and surprisingly a large Raphael catfish.  It seemed that my clown disregarded any bottom dwelling fish (though not sure if it's true with all clownfish).  As for other tankmates, the requirements are that they must be fast fish, in case the clown does get testy.  The tankmates can not be aggressive, if a clown knife should become injured, or it's anal fin damaged it will not be able to swim.  And the fish will stress itself to death. Cichlids are not to be kept with knives.  And the biggest concern is that the fish need to grow faster than the mouth on the clown (which will grow quickly).  They will need to be big fish.  If these fish are larger than the clown can swallow, then the clownfish will not even care about them.
Other concern with the clown is that you will need to offer it a place to hide.  I used a large piece of driftwood in my tank along with giant fake plants (4 feet long varieties).  This made a natural looking wall for the fish to hide behind, thus making it more comfortable.  I also found that I only left one side of my tank lights on (the side opposite the hiding spot).  As well as have one of the plastic plants floating on the surface of the water, shading much of the tank.  Clowns prefer to hunt at night, and don't typically come out during the bright day.  Doing this I found my clown would tend to come out more often during the day without the intense lighting.  Be sure to get your clown on food other than live fish.  I spoiled mine when it was young by only feeding it feeder fish and when it was older I couldn't get it to switch easily.  I found myself purchasing 2-3 dozen goldfish ever couple of days to feed it.  Fact: An adult clown knife can eat 2 dozen medium sized goldfish in a single night.  Good luck on the fish.  They are very enjoyable, and quite impressive. -Magnus>

Everybody To The Limit! - 04/13/2004
I purchased a knife clown about 5 days ago.  He's about 3 to 4 inches long.  
<Aww, just a little baby!  Just to check, you do realize that these beauties get over four feet long, yes?>
I have him in a 30 gallon tank with 2 gouramis, 2 tiger barbs, 2 angels, a large pleco, a 4 inch silver dollar, a small Cory cat, a small tetra, and a kuhlii loach.  
<Uh, and a partridge in a pear tree??  This is, nicely put, a little much for a 30 gallon tank, I'm afraid.>
I realize knife clowns grow rapidly and that I will not be able to keep this one in my tank for long.  
<Or any tank....  A few hundreds of gallons would do for a couple of years.>
However, I have fed him fish flakes, freeze dried plankton, freeze dried Tubifex worms, brine shrimp and feeder guppies, and he has exhibited little to no interest in any of these.  I have yet to see him eat, though he swims around freely during feeding time.  
<Try frozen bloodworms, pieces of krill, squid, prawn/shrimp.... and skip the feeder guppies, unless you breed them yourself; they run a *terribly* high risk of giving your fish disease.>
All the other fish chowed down.  I have also noticed that his fins are nipped.  
<Uh, not to be cruel or anything, but what do you expect?  A thirty gallon tank is not suitable for the sheer volume of fish you've got, and *especially* not suitable for a knife capable of growing taller than your average school kid.>
I have noticed the silver dollar nip at him a couple of times.  
<I would not doubt it.  The barbs are undoubtedly to blame, too.>
Any suggestions?  
<First and foremost, I would forget about the knife for now.  I hate to be harsh, but there is just not a place in your tank for such a fish right now.  If the stress from the crowd doesn't kill him, the barbs and silver dollar will, I'm afraid.  Then I'd recommend focusing on how to hone down your bioload some; characins are schoolers, and need to be with others of their kind to thrive; you might consider doing a separate tank for the silver dollar, and get him a couple pals, and include the barbs in that tank, and the tetra with some friends, too.  That would take you down to two Gourami, two angels, a pleco, a Cory, and a Kuhli in your 30g.  The plec will be next to need a bigger home, if he doesn't already; you implied that you planned on moving the knife to a bigger tank - perhaps instead, you could upgrade, and move this batch (Gourami, angels, plec, Cory Kuhli) into the bigger tank, leaving the characins in the 30g?  I'd add a couple more Corys and a couple more Kuhlis, too; they, too, are better in groups.  Then, after that's settled, you might like to consider Xenomystus nigri, the African Knifefish, for your larger tank.  This is really the only knife available in the trade that will not grow far too large for the average tank; they top out at about eight inches.  Here's fishbase's rundown on 'em:  http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=5065&genusname=Xenomystus&speciesname=nigri .>
I am at a loss for what to do next.
<There is really nothing you can do to make the current mix work....  I do not foresee the knife surviving in the current scenario.  I hope that this has been of assistance to you....  Please forgive the "nagging"; I only have the interests of you and your fish in mind.>
Thank you in advance, Mariella
<Wishing you and your finny pals well,  -Sabrina>

Ghost Knife Changing Colors
What causes a black ghost knife to start to lose its color and turn a silvery white?
<The first thing I would do is test my water, poor water quality, stress, age, diet, there are many things that can attribute to these fish changing color.  Gage>

Clown Knife and Algae Eater
Hey, I just bought a large-size clown fish with 2 other medium-size tropical fish in a 55 tank. I've learned that  the knife is a predator and will eat anything smaller than its mouth. I'm concerned that if I put an algae eater in, the knife might swallow it as food.
Since my tank is full of plants and rocks, it'll be difficult to clean the algae. What should I do!? Thanks for your time.
<<Hello. The best way to control algae is by doing waterchanges. Once your tank is established, test your nitrates regularly, and do the waterchanges accordingly. Algae thrives on organics in the water, and even the best filter will not prevent build-up of organics, you need to remove them by doing partial waterchanges. Especially with a large predator in your tank, weekly waterchanges will be necessary. Is this tank still cycling now? You must test your ammonia and nitrites as well, each week! And keep in mind that your clown knife will eventually outgrow a 55 gallon tank. You will need to upgrade if you want to keep him alive.
-Gwen>>

Knives, Spines, Rope and Fire. OK to add Claws?
Hi, thanks for the info that you've given me so far, but I've got another question. I've got my 130 gallon tank set-up with a 10" clown knifefish, 12" spiny eel, 6" fire eel, and 12" ropefish. <No guppies or swordtails for you, huh?> I also own two African clawed frogs (about 4" long each) that are being kept at my mothers work. I'm wondering if I would be able to put the two frogs in the 130 gallon tank. In your opinion, do you think that the clown might decide to take a bite out of the soft, fleshy frogs, or would he leave them alone? Right now, the clown eats 3" long goldfish, but I'm trying to get him to accept frozen shrimp. <A bit risky, IMO. A Knife will eat anything he can fit in it's mouth. Even if he only tries, he may kill or injure the frog. Not a great mix. Risk would be reduced if the Knife was off live food first and kept well fed. The eels may even cause problems at night, but less likely.>    
Also, one other question.  For my 130 gallon tank, would a Classic Eheim 2215 canister filter and a Fluval 404 canister filter be enough for the tank? I'm going to be adding more fish to the tank than I have now and prefer to have above average filtration. If the filtration isn't enough, what's a good filter that I could add to the other two? <Each are rated for around 100 gallons. You should be fine as is, but those are some pretty large fish in there, and growing. I'm a big fan of Marineland's Emperor 400 for bio filtration. Surely wouldn't hurt to add the bio wheels to help with ammonia processing.>
Thanks for all of your help.
<One last point, which I'm sure you knew was coming. Try very hard to get the Knife off live fish. Hard to do, I know. But unless you can QT the feeders, sooner or later you WILL (not "may") bring Ick or some other nasty into your system. Treating a 130 with these large fish will be a challenge to say the least. Don>

African Knifefish - 11/03/2004
I recently bought a brown knife fish.
<Xenomystus nigri....  Usually called the African knife, sometimes sold as the brown knife.  Is this your fellah?  http://www.fishbase.org/Summary/SpeciesSummary.cfm?genusname=Xenomystus&speciesname=nigri  There *is* a fish more similar to the black ghost knife referred to as the brown ghost, but I've only seen this fish once or twice offered for sale.>
(It's been about 10 years since my last aquatic impulse buy. I was due.)
<Tsk tsk....  ;) >
I put him in a 55 gallon  aquarium containing 5 hatchets, 7 harlequin rasboras, 5 zebra danios,
<All of these may one day be food....>
1 sunset gourami, and 3 Cory cats. He doesn't seem to be bothering any of them. He's  only about 4" long now. Brown knifes don't get as big as clowns, do they?
<Hoo, goodness, no!  The clown gets over four feet long!  The African knife is, perhaps, the *only* regularly available knife suitable for your tank, topping out at about 12", and often a bit smaller than this.>
Will  my tank be big enough if I don't add any more fish?
<I believe so.>
When he gets bigger, will my  other fish be in danger?
<Plausibly.  I would try very hard not to be too attached to your smaller fishes, right now....>
Since I don't get to see much of him, how do I know if  he's getting enough to eat?
<Feed after lights-out on the tank.  Leave a small light on in the room the tank is in; just enough for you to see by.  After waiting an hour or so, sneak in with some stinky yummy treats (I've seen these relish frozen bloodworms like nothing before!) and wait until he finds it.  You can use a cone-type worm feeder.  If this doesn't get him biting, you might try live ghost shrimp or live blackworms; the former is the "healthier", "safer" choice.>
How do you feed live earthworms to them?
<After lights-out, try holding the worm by hand so that some/most of it is in the water near the knife.  Wait.  See if he bites.  Don't fear, eventually this fish will be easier to feed, and will recognize you as the bringer of treats.>
I know from past experience (with fire belly newts) that they try to burrow into the gravel before they get eaten. How do I keep the worm where the knife will find it?
<Again, try by hand, or perhaps you could use a dish of some sort to place the worm in?>
I really appreciate any advice you can give me.
JoLynn
<Good luck with this new knife....  One of my favorite oddities, by far!  Wishing you well,  -Sabrina>

Feeding Clown Knife – 03/17/07
Hi –
<Hello Ray, Brandon here.>
I’ve had a clown knife for a couple of months now, and during that span it has grown from 3 – 4 inches to 6 – 7 inches. At first, when he was smaller, I fed him a combination of brine shrimp and blood worms (frozen) along with small (not goldfish feeders) fish. However, I had to leave for college during that time (I got it during my winter break), but not without telling my parents what I would like them to feed it (e.g. continue feeding it brine shrimp and blood worms along with the occasional fish). However, they started to feed it the minnows that are commonly found in pet stores.
<Mmmmm.  Minnows are bad news.  This is a really good way to introduce disease into the tank, and to your fish.  Ever hear of hole in the head?  This is one of the ways that your fish can get it.>
So, upon coming home for spring break, I find that my clown knife refuses to eat anything other than brine shrimp and blood worms along with live fish.
<Define anything.  Have you tried any other crustaceans?>
Given his size now, wouldn’t brine shrimp and blood worms be too small and not nutritious enough for him?
<Depends on how much you give it.  It is never a good idea to stick to one variety of food though.>
I went out and bought frozen krill in order to try to wean him off of live fish but he refuses to eat them. He just lets them drop to the bottom before proceeding to ignore them (the first time I
put them in he ate one but then quickly spit it back out and since then has ignored them).
<Seems that the Chitala chitala does not regard these as food.>
I even tried cutting the individual krill into smaller bits in case they were too large for him. Thus, I have not been feeding him anything lately (this has gone on for about 3 days now). Just wondering, how
long can I go without feeding him without starving him to death?
<Three days is not going to starve him, but it will definitely stress him. I would say it might take a month or more before he starves to death.>
Also, what is the best way to wean him off of live foods (save for an occasional snack) and what food should I use to do this (if not krill)?
<Krill is not really a part of this fish’s natural diet.  It is quite possible that you will never wean him off of live food.  I have had to come to this realization, with one of my saltwater fish.  I would say that the best way to proceed when faced with this sort of thing, is to set up a 10 gallon tank, with some gravel, and a plant or two, and put about three dozen ghost shrimp in it.  Feed them a high quality food (gut loading), and give the Chitala chitala about three - four a day.  If it is taking blood worms, you might try mixing something that you want it to eat with them, eventually the fish will ingest the other food, and could start to recognize it.  Another resort is to try a small piece of store bought fish attached to the end of  a feeding stick, wiggle it around and see if the fish takes it.>
Finally, I have one final question that has nothing to do with feeding him…… sorry.
<No worries.>
I plan on building a new tank him during spring break, but I have read conflicting reports as to how large they will get. While I know that they grow to 4 feet in the wild, I have read that they usually don’t grow past two feet in captivity.
<I don’t usually show up late for work but it happens.  I would plan on a four foot max length just to be on the safe side.  There is no guarantee that this fish will get to four feet, but there is no guarantee that it won’t either.  Everywhere I have seen them sold, I have seen a sticker posted that stated that the max length was 48 inches.>
However, I have also read in some places that they can grow up to 3 – 3 ½ feet in captivity. So my question is this – how large can I expect my clown knife to get and based on this, what size tank should I make with what dimensions?
<I would plan on four feet.  I would also advise you to go and buy the tank.  Shoot for 150 gallons.  It will cost about the same to buy the tank, as it will to make it, and the store bought tank will most likely be (not to insult your abilities.) more well made.  But since you asked, I will say that the dimensions should be something like, 72 ½ inches long, 18 ½ inches wide, and 28 ½ inches high.>
Thanks for taking the time to read this long question and thanks for making such a great website (I’ve read through many articles and FAQ’s just for fun…. Wait, is that bad? :-) ).
<You are most welcome.  Thank you for the kind words.  Good luck with the Chitala chitala.  Brandon>
-Raymond

Freshwater tanks - African Knifefish question, cichlid in/comp.    12/28/06
Hi there.
<<Hi, Stacy. Tom here.>>
Can I put a Black African Knife Fish in with a couple of African Cichlids? Just starting a new tank and am not sure of this.
<<It depends a great deal on the size of the tank that you’re starting, Stacy. Less than a 50-60 gallon tank would be too small. These fish can grow to a foot in length.
Factor in the size of the fish you want as tank mates as well. Compatibility-wise, they need to be with large fish since smaller fish might look like “lunch”. (Tank size again.) You’ll need to provide cover, i.e. hiding places, for them since they’re not particularly active during the day. Beyond this, your question is a bit difficult to answer without more information regarding what I’ve already mentioned and the species of Cichlids you’d like to house your Knifefish with.>>
Please help.  Thank you.
Stacy
<<You’re welcome even though it’s only a start. If this isn’t enough to go on, you know where to find us. :) Happy Holidays to you. Tom>>

Clown Knife Life-spans in wild/captivity  - 12/07/06
First thanks for the excellent site and knowledge, when all else fails
you guys have the answers.
<Welcome>
I have been researching the Clown Knife (specifically Royal Clown Knife - Chitala blanci) life-spans.  I am about to adopt a pair from a friend that have been raised in a 300 gallon tank for the last 2 years from 4" to 16" each.  I am moving them both into a 240 Long (96x24x24).  I am very interested in the average lifespan of them in captivity or in the wild.  Can't seem to find much on the net to support an educated guess.
I have read that they rarely grow past 24" in captivity, but can reach 4' in the wild (may be pushing it IMO).
Thanks for any insight you can provide.
Joe
<I've been to the "new" Bangkok aquarium just two months back... and they have some Notopterids of this and related species that they've had for teens of years. Unfortunately fishbase.org doesn't have a chart/data for this species' length/age relationship... in the wild. Bob Fenner>

SICK JACK THE KNIFE
I have an African Knifefish and it is pretty hard to find useful information about this species. I have a 55 gallon tank that recently got ich as a result of a fairly new clown loach. The loach died and gave it to a danio and another loach I had. I raised the temp to 85 degrees and I have raised the salinity to 1.003. (Over a period of a few days of course). The loach's spots went away as well as the danios and I haven't found any other traces of ich. 
Things have not been going well however. Yesterday, I found a dead African dwarf frog and today I found a heavily bloated danio who is probably dead by the time you read this. My other danio looks like his stomach is protruding a bit as well. I checked my knife and he has these two big patches of white. I didn't know if it was ich because it isn't small dots it is a very large patch (about 3cm) and another patch (about 1 cm). 
I have two small Plecos that I haven't noticed any problems with and I really don't want anything to happen to my knife. Are the large patches ich or something else? They have just showed up today and were not there yesterday so I am
catching it pretty early. Any suggestions? Thanks for any help and great site.
< Your tank is breaking down from the water treatments. Drop the water temp to 78 to 80 degrees. The high water temps are stressing your danios and causing the bloat. Do a 30% water change, and vacuum the gravel. Service the filter too. Check the ammonia and nitrite levels, they should be zero. Check the nitrates. They should be lower than 25 ppm. Now that the tank is cleaned up you need to treat those bacterial infections on the knife fish. Use Nitrofurazone and back off on the salt. This medication may affect the good bacteria that breaks down fish waste so watch for ammonia spikes.-Chuck>

Request for bibliographic help on the Featherback Knifes, Notopteridae
Dear sir
This is sathish s v from India working for PhD on induced breeding in fish n notopterus . hence I am in need of your valuable references (reprints) related to the above .kindly send them to the below find address.
<What little I have is mainly pet-fish related and referenced (the intended use) and posted here on our site: http://wetwebmedia.com/bonytong.htm
Bob Fenner>
SATHISH S V
DEPARTMENT OF ZOOLOGY
GULBARGA UNIVERSITY
GULBARGA -585106
KARNATAKA, INDIA

Clown knife with a bulge
My clown knife looks as though it has swallowed a small rubber ball.. the kind that you get out of a gumball machine...   All of my other fish are still in the tank and still have all of there parts... my clown knife will not eat now but is moving around fine...
<Is the clown producing feces at all?  If so, is it normal and brownish, or white and stringy?>
We have had Mercury for 2 months now and have NEVER seen this before... I understand and have seen the "bulge" after eating, but this is NOT that!! The bulge he has now is huge and very round, again, like he swallowed a rubber ball.. no other way to describe it...
<Sounds very much to be a gut blockage or constipation.  I'd suggest to dose the tank with Epsom salts at a rate of 1 to 2 tablespoons per ten gallons (this *should* help), and if the fish looks like he may accept food tomorrow, offer daphnia or mosquito larvae, or possibly (depending on size of the fish) a small earthworm, if the other items are too small for him.  These foods are high in roughage content and may possibly help to pass the blockage.>
The owner of the local pet store thought maybe it was a bladder infection
<Hmm....  a swim bladder infection is characterized by abnormal swimming (and occasionally accompanied with dropsy) - I do not believe this to be the case.>
and told me to wait until tomorrow and see how he was....
<Go ahead and dose with Epsom salts tonight, it may very well help a great deal.>
I cannot find ANYTHING on the net regarding this.... CAN YOU PLEASE HELP?????
<I do wish to bring up another issue that this may be - there's the possibility that this is a tumor.  That you seem to imply that it happened suddenly and that the fish is not eating lead me to think constipation far more likely.  If it is a tumor, though, there's really nothing to be done, unfortunately.  Hopefully you'll see some improvement soon.>
Thank you in advance....  Heather O
<Wishing your fish a quick recovery,  -Sabrina>

Clown knife with a bulge - II
THANK YOU very much for the speedy reply!!!!!  
<You bet!>
This morning when we checked in on him.. the one side has gone down completely and the other side is much smaller but now , no other way to explain it.... but it looks like a huge zit with a white head... half an inch long by 1/8 of an inch wide...
<Hmm.  That doesn't sound good.  possibly an injury, perhaps infection....>
it definitely looks better than last night at 9:00pm....
<That's certainly a good sign!!>
as for producing feces.. I am not sure...
<Sounds like he passed the most of it.  Still, do try to feed foods with a high roughage content for a few days.>
Mercury is about 7 inches long now... and has been doing wonderful until last night... he gets along great with our other clown knife Neptune, who is about 12 inches.... we also have a convict, a scat, an iridescent shark, and a plecostomus...all live happily together....
<You seem to have a taste for the very, very large....  Ultimately, hope you've got a really big tank!  ;)  >
He still isn't eating... but as I said.... I think that he looks much better....
<Good.>
Again, thank you SOOOO VERY MUCH for the speedy reply... this is a site that I will keep handy in the future!!!
<Excellent.  Pass it along to all your fish friends, too!>
Oh, I almost forgot... I do have aquarium salt in the tank... but will add Epsom salt if you still think that will help!
<I do think it would help, perhaps, especially if Mercury is still a little bloated.  Also, please keep a *close* watch on that strange mark - if it's an infection of some sort, you'll want to quarantine and treat with an antibiotic.  Hope all goes well, and glad to be of service!  -Sabrina>
Heather O

Clownin' Around - Clown Knife Behaviour - 12/03/2004
I have a 55g. tank with two clown knife that are about 6 inches in length, along with a glass cat, a Pleco, and a fiddler crab.
<A few problems, here - not the least of which is the size and territoriality of the clown knives.  Please note that the glass cat may likely end up as clown food, and the fiddler crab really requires a way to get out of the water for long-term survival, and really ought to be in saltwater - or at least brackish conditions.>
They are all doing great together, however, my one clown will go over to the other side of the tank near the other clown knife. They do not pick on each other but they rub their bodies together for a few seconds then they go their separate ways.
<I would assume that this is either courtship or aggression - and far, far more likely to be aggression.>
Also when the one clown gets close to the other one, he ends up rubbing his body up against the rainbow rock I have in the tank. He does this in front of the other knife fish only, like he is marking territory or showing off. I see no signs of any parasites, no ick, no frayed fins, great appetites as well.
<I would guess this is part of the aggression issue - but possibly an indicator of gill parasites.  Please observe the fish for heavy breathing or any other abnormalities.>
My knifes even come out and swim during the day until I get too close to the tank.  All in all, I have been watching them very closely for any signs of illness, I am out of practice as far as fish, I worked in a great pet store for 10 years and kept up to date on every single animal we sold so that I could give the best information as well.
<Always wonderful to hear of reputable fish stores - thank you for being informed on your livestock!>
But clown knives were not one on my list, my boss took care of those strictly.  Can you think of any other reasons why the clown knife would be doing this in the presence of the other clown knife only?
<If there are gill parasites or another ailment at play, it could be purely coincidence - perhaps the "best" rock to scratch one's operculum on just happens to be next to the other knife's digs?  Otherwise, again, I might attribute this to a display of aggression/territory, as you suspected.>
He doesn't do it any other time at all and the temp is usually around 78 degrees F, ph is around 7.0, I keep up on water changes and monitor levels and test regularly as well.  
<I am assuming, then, that ammonia and nitrite are at zero, and nitrate is below 20ppm?>
Also I was keeping a few red eye tetras, some head standers, zebra Danios and some swords in with the knives. I had to take them all out and put them in another tank because the knives were tormenting them to death.
<Heh, yeah - all of those would make tasty snacks for the knives!>
A few got ick and the knives are still fine after I took the other fish out. Which they did eat a few of the Danios and a red eye as well.
<This is concerning.  How long ago were the fish removed?  It is quite possible that the knife does, in fact, have ich on its gills.>
I know they are eating well. I read all the info you have given to everyone on knife fish and it was very educational for me as well.
<So glad to hear this!>
However I did not see in great detail about the actual personalities these fish generally have.
<Well, to be honest, not a great many folks can really provide adequately for this species....  Cared for properly, the fish can and should grow to be roughly four feet in length - a four-foot fish requires a *much* larger tank than would easily fit in the average living room.  And keeping them just while they're young isn't really the greatest idea - what will you do when they hit a couple feet, have outgrown the 250 gallon tank you've upgraded to for them, and can't find a public aquarium that is willing to take them on?  Please think very seriously about the ultimate size of this fish, and what you plan to do as they age.  If they are already intolerant of each other at six inches in a 55g tank, imagine what they'll do to each other in another foot or so, if they allow each other to live that long....  At the very least, I would remove one of the knives.>
Sorry this is so long but this is pretty much the only web site I could find that has a lot of valuable info on it pertaining knife fish.  
<And thank you very much for writing in, and thereby helping us expand the information available.>
Also if you think my clown knife does have parasites or some other disease, what should I be treating him with? I know there are many meds out there not to be used for scaleless fish, and I suppose the parasites will spread to the other fish in the tank as well?
<You are correct on both accounts - knives, especially, are tremendously sensitive to most medications.  I would avoid treating the fish with medicines at all costs.  Watch the "scratcher", and if you begin to suspect that he has ich, I would add salt to the tank.  Be sure to use a salt marketed for freshwater aquaria, and test on a sample of your tank water first to ensure that the salt will not alter your pH undesirably.  I would slowly (over a few days) raise the temperature to the mid-80s (84*F-86*F), increase the salinity to a specific gravity of 1.003 (use a good hydrometer to measure this) and hold it there for at least a week - perhaps a little longer.  Always make salinity changes VERY slowly - spread the change out over a few days.  The ich cannot survive at this salinity, and the temperature increase will cause the ich to speed up its lifecycle to bring it to a vulnerable (killable) point in its development sooner.>
Thank you for any info you can give to me.
<And thank you again for writing in.  It seems as though you greatly enjoy the knifefishes.  I would like to recommend, if you choose to relocate both of the clowns due to size issues, that you consider Xenomystus nigri, the "black" or "African" knifefish.  This little fellow won't get much more than eight inches in length, and has many of the same qualities of the clown (same general shape, temperament) packed into a MUCH more manageable size.  Though it lacks the beautiful markings, it is still a very attractive, very interesting fish, and I highly recommend it.  It would live quite well and happily in your 55g, for the full duration of its lifespan.  Please feel free to write back if you have any further questions, and thanks again for writing in!>
Shannon
<-Sabrina>