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FAQs about "Freshwater" Morays Eel Foods/Feeding/Nutrition

Related Articles: Freshwater Moray Eels, Moray Eels, Other Marine Eels,

Gymnothorax tile not eating – 07/27/08
Hi guys,
<Hello Erin.>
I have owned a tile for about 8 months, he has recently stopped eating. I have been keeping his salinity at approx 1.010 and the temp about 28 degrees.
<Are you using marine salt intended for marine aquariums, not “aquarium salt” or something else? Do you use a hydrometer or refractometer to measure the actual salinity/specific gravity?>
I have added plenty of rocks and caves for him to hide in and I have had the water tested, everything is as it should be.
<Which would be nitrates below 30 ppm and a pH between 7.5 and 8.4. No nitrites or ammonia.>
His diet was mainly frozen krill and green peeled prawns.
<This diet of only crustaceans needs vitamin additions, esp. vitamin B. More variation would be beneficial.>
He has not eaten for about 7 weeks and has no obvious signs of sickness, I am thinking about making his tank full marine as it is the only thing I have not tried.
<I agree, this might help. Don’t raise the salinity too fast, though. You need to avoid killing the filter bacteria. 0.002 to 0.004 per week is enough and measuring ammonia and nitrites will help you to determine if the filter bacteria are still working. The rise should be done with large water changes.>
Any advice would be much appreciated. Regards, Erin
<7 weeks appears like a long time for a hunger strike, but is not life threatening per se. The reasons for hunger strikes are often not known, sometimes the eels are overfed, sometimes the environmental conditions have to be improved, sometimes permanent damage has been done by improper diet and/or keeping in the past. As long as the eel has not lost too much girth and has no internal damage (which we cannot determine) it likely can survive. If it starts eating again, you should offer a wider variety of food and provide enough vitamins that way. Especially vitamin B can be destroyed during some freezing processes, and krill should not be the main staple. Please also see http://www.wetwebmedia.com/ca/volume_4/V4I2/Freshwater_eels/freshwater_eels.htm . Good luck. Marco.>

Re: Gymnothorax tile not eating – 07/29/08
Thanks Marco,
<You are welcome, Erin.>
The salt I have been using is marine salt called "Red Sea" but for the conversion over to full marine I have been buying in marine water.
<If your salt can be used for marine tanks, it is okay.>
I took out 20 litres and replaced 10 and will continue to do this every 2-3 days until I have reached marine level. Is this too fast?
<Depends on the tank size, of course. Your hydrometer will show it. For a 120 l tank this is sufficient and can be done 2-3 times a week. In a larger tank you may change more.>
What is the best food to feed him in order to provide him with Vitamin B. I have put in feeder shrimp but he so far he is ignoring them.
<The fresher the food, the higher the vitamin B content in general, even in frozen food. But in krill it appears to be very low. It is also possible to add vitamins from the pet shop. Let’s see if the feeder shrimp vanish. In general they also love mussel flesh, scallops, clams, pieces of marine fish, prawns, shrimps and squid. Use as much variation as possible, (I buy unseasoned seafood mix intended for human consumption) and you’ll supply him with all he needs.>
I have been using a hydrometer to measure the salinity. I added the 10 litres of marine water last night and there is no change as yet to the reading, does the temperature of the tank affect the salinity?
<Not the salinity, but the specific gravity, which is what you are measuring with the hydrometer. Specific gravity or SG are numbers like 1.010. Your temperature is okay, but can be cooler (about 24-28°C). >
I have read the page you wrote about the eels, I have found it to be the most informative site yet which is why I wrote to you for advice.
<Thanks.>
Thank you again.
Erin
<I wish you good luck with your moray eel. Feel free to mail if changes occur (symptoms for disease, decline), if he starts eating again or if further questions arise. Cheers, Marco.>

Update on Erin's moray eel – G. tile – 08/04/08
Hello Marco,
<Hi Erin.>
I have done all water changes etc,
<What is the salinity now? Nitrates?>
there doesn’t seem to be a marked change in the eel, as far as I see he still isn’t eating
<Are the feeder shrimps still there?>
but I did seem him out swimming and for the first time in a while and noticed a pink spot about the size of a small coin near his anal region. I wonder what this could be and if you have any ideas.
<The area around the anus is cream to pink coloured at this species. If this is what you observed, it is no reason for concern.>
Many thanks Erin
<Did you try any other food like mussel flesh or a small piece of squid? Are there any symptoms for a disease? Good luck. Marco.>

Re: update on Erin's moray eel – G. tile – 08/05/08
Hi Marco,
<Hello Erin.>
Thank you for the reply. The water conversion is still slowly going on, the salinity is about 1.013 on the hydrometer,
<Sounds okay. I’d continue the water changes with salt addition.>
nitrates read normal,
<The less nitrates, the better.>
but he does seem a lot happier and more active. The feeder shrimp I think grew too big so I bought 10 smaller ones, it is hard to try and count them all, as some have died and the others have eaten them.
I bought the seafood mix and tried some squid and mussel flesh,
<Very good.>
but still no go!
<If he starts eating again, he surely will enjoy it. I’d continue trying it every few nights with small pieces.>
He still isn't showing obvious signs of sickness or loss of weight and his colour still seems normal...
<Sounds good. It appears you are doing everything right, the rest might be up to the eel.>
If I did overfed him in the past, how long would he fast for if this is possibly what he is doing?
<The longest fasting periods of moray eels in general that are documented were between 8 and 10 months (those eels survived). So there still is a lot of hope, but I know this can be nerve wrecking. If this eel has no internal damage I am confident it will eat again.>
Thanks again, Erin.
<Thank you for the update. Best wishes. Marco.>

Feeding a freshwater moray eel 06/14/08
hi,
first of all what a great site!!!
i brought a moray ell 3 weeks ago. he is in my freshwater 30 gallon tank that has been up and running for about 2 months with some small loochs and sucker fish.
The ell is 12" long and looks a bit like a Muraena helena. he has the sticking out nostrils and is coloured light brown/beige with little yellow/white spots on his body with a small fin along his back.
do you know what type of ell this is? i will try and get a picture from my friends camera.
The other question is about him feeding
He has been in the tank now for 2 weeks and seems happy. he comes out when there is no one watching and when the light is off but most of the time sits in his hiding pot.
i have put live shrimp in the tank over the weeks and they have all gone but my loochs eats them so im not sure if he's been eating, as i have never seen him eat. he's not interested in shrimp meat, or dead dilles.
im wondering if he's ok or if he needs something else to eat
thanks a lot
chris
<Hello Chris. The so-called 'freshwater moray eels' are in fact brackish/marine fishes. There are several species in the trade, but by far the commonest is Gymnothorax tile, a pinkish-brown species covered with tiny yellow spots, and that's the species you likely have. They do not do well in freshwater permanently, and most simply die after a few months. Given morays can easily live 10+ years when maintained properly, there is absolutely no justification for keeping them in freshwater (or for that matter for retailers to sell them as freshwater fish). A common symptom of insufficient salinity is a lack of appetite, which is what you are seeing. At minimum, you need to maintain them at SG 1.005 (about one-quarter normal seawater salinity), and many would argue (myself included) that at least half-strength seawater (SG 1.010) is required for permanent success. Obviously they cannot be combined with loaches or other freshwater fish. Moray eels are primarily nocturnal and hunt by smell. This means you can't combine them with more active nocturnal fish. Some specimens remain good community fish their entire lives, provided they are combined with tankmates of equal or larger size. The best approach seems to be to keep them either alone or in groups. Others become more aggressive and will bite bigger fish even if they cannot kill them. Do read Marco's excellent article on these fish, here:
http://www.wetwebmedia.com/fwsubwebindex/fwmorayart.htm
Once you've digested that, review how to create a brackish water aquarium here:
http://www.wetwebmedia.com/BrackishSubWebIndex/bracsystems.htm
Because eels aren't terribly active, you don't need a huge aquarium; 125 litres/30 gallons is ample for a single specimen, particularly if you have high capacity filter and do regular water changes. At high salinities, a protein skimmer will help a lot too.
Hope this helps, Neale.>

Gymnothorax tile eating questions, Proper food for Gymnothorax tile – 06/12/07
Hello! <Hi Amanda.> I just love your website!! So much information!
<It’s great you like it.>
I have a wonderful Gymnothorax tile. I have had him (I'm not sure how to sex them, so I just call it a him) <Will compose an article on sexing moray eels in the coming months.>
for about 2 years now and he's doing wonderful. He has grown a lot since I first got him and is a joy to watch him at night. <Sounds good.> At the moment he has a selection of ghost shrimp, rosy minnows <not appropriate feeder fishes.>, and a few guppies. He has the tank to himself except for feeder fishies. He has his own awesome cave that he sleeps in all day. And other rock structures, plants <freshwater or brackish water? Hardness? If fresh, are you sure it is a G. tile? 2 years in freshwater would be an exceptionally long time of survival for this species.>, and tubes to hide in when he's out at night. He likes to hang out in one of the tubes and wait for fish to swim in. He's a lazy hunter sometimes. <Sounds familiar.>
I have 2 questions about feeding him.
1) Should I leave the smart fish in the tank? It seems that with every sacrifice, a few fish are smart enough to learn that the eel cruises the bottom of the tank for food and so they stay at the top, safe and uneaten. The eel tries his best to eat the little buggers but they are just too fast for him. Some have managed to stay alive long enough to grow big enough that the eel isn't interested in them anymore. Should they remain in the tank or be removed and "freed" to their own tank? Is it bad I feel like the Emperor of Rome, deciding if the gladiators (fish) die or be set free? Hehe
<Removing them would be good to avoid overfeeding, which is a common reason for the short lifespan of captive moray eels. Like humans they tend to eat more than they need. If you enjoy the fate of the feeders is your own decision. I prefer feeding frozen food and use feeders only for freshly imported specimens or to train difficult species such as Rhinomuraena quaesita and Pseudechidna brummeri. I consider frozen food to be more simple and safe. See this very good article by Neale: http://www.thepufferforum.com/forum/library/feeding/feeders/ on the ethics of feeding fishes and appropriate species. See http://www.wetwebmedia.com/ca/volume_4/V4I2/Freshwater_eels/freshwater_eels.htm for proper care for G. tile. I’d stop feeding minnows and vary the diet with sea food.>
2) I have been reading the eels prefer crustaceans <Some species do. G. tile eats almost anything mobile including most crustaceans.>. I did at one time attempt to keep a larger shrimp (name escapes me atm) in the tank. That lasted all of one night. Eel gobbled that guy up, even though it was fairly large. My question is, would feeding him crayfish be okay? <Yes, as long as the diet is varied.> Eel is about 16 inches long (I'm not brave enough to try and actually measure him, nor do I want to stress him out trying to) and about as big around as a quarter. I am worried that the crayfish could hurt him or the eel get hurt trying to eat the tough shelled guy. <You could freeze the crayfish before feeding it to the eel.>
If it is okay, what size range would be safe? Of course, the smaller the better, but what would be considered too big?
<About the size of the head of the eel (1-2 in.) should be safe. Larger ones could try using their claws, although I think they would not be able to cause serious wounds as long as you don’t throw some lobsters in there.>
Thanks so much!
Amanda.
<Hope that helps. Marco.>

Eel eating habits 9/23/06
I have a brackish water moray eel that is albino
<Unusual>
that has been doing very well. I have had him for about eight months now. The only concern I have with him is he is beginning to eat more than he has been. Can he eat too much?
<Mmm, yes, possible>
I place some guppies and ghost shrimp in for him to eat at his pleasure. He has been doing well except recently he has been eating more than usual. Is this abnormal or something like a phase eels go through?
<Can't say>
I have added a butterfly goby and a few other fish but they are too small for guppies as food and the only other fish capable of taking guppies was my leopard bushfish and he died (I believe he may have been stuck by the butterfly goby as one of the two I bought was also found dead). I have watched my eel gulp a shrimp or two then continue to go after guppies and just keep trying over and over. He used to not eat like this before. Is there any reasons I have given here or that you can think of for such a voracious appetite?
<Mmm, no>
One last question on eels in general. I have heard that all eels go to the Sargasso Sea to spawn. Is this true or is it a specific species that does this? Thank you
<Anguilla rostrata solamente. BobF>

Freshwater snowflake moray
I got a snow flake about 2 weeks ago and it wont eat I've tried all sorts of food (Tubifex worms.. live...crustaceans..) please help ... please mail any info you might have thanks
<Do have patience... these Eels frequently go on food strikes when first moved... do keep trying various meaty, live foods, including smaller earthworms (like those you can dig up, or buy at bait stores), and if your other fishes, plants et al. can tolerate it (they should), do place a teaspoon per ten gallons of non-iodized salt (ice-cream, kosher, pickling...) in this system... should help stir appetite and act as a general cathartic.
Bob Fenner>

Freshwater Moray Eels
I really appreciate the time that you took for this site.
<Ah, you're welcome. It was made for you.>
I would like to buy a fresh water Moray Eel. I guess I need some help and no one in pet stores really know anything about freshwater. I am going to put it in a 75-100 gallon tank. What kind of sand should I put down?
<Something fine/r... and calcareous. Please see the "Marine Substrates" section and "Moray Eels" under the Marine Index (the freshwater species are touched on there)>
Is possible to order a fish through the mail?
<Certainly>
Can I feed them gold fish? And better yet how about a book on fresh water moray. This would really help.
<Not really goldfish, but other live or frozen/defrosted meaty foods. Take a look at the WWM site cited, then fishbase.org then your search engines under "Freshwater Morays">
Thanks,
Michael
<Be chatting my friend. Bob Fenner>

Freshwater morays
Hi Bob,
I have been reading the FAQ on freshwater moray eels and was wondering if you could help me out with a query of mine.
A friend of mine recently acquired 3 freshwater morays directly from a wholesaler. He was informed that they were a freshwater species and that the specimens were actually bred in captivity in freshwater.
<Really? Hmm, have just this last week finished spiffing up this section of WWM... no Morays (Muraenidae) have been spawned, reared in captivity... the larval history phase, the leptocephalus, is very problematical...>
He does not have the Latin name but we believe them to be Echidna rhodochilus and they range in colour from a peppery speckle to whitish.
<Yes... wish I had better pix of the white and black geographic "races"... very beautiful>
I am surprised to hear that they were bred in freshwater but apparently this is the case. They are about 4" long and currently being housed in a 20 gal aquaria where they are doing well and feeding on river shrimp.
<Neat>
Due to the eventual size and conditions they require he has offered them to me as I have a 150 UK gal brackish tank housing Figure eight and green spotted puffer fish.
I am interested in taking these fish but am wondering if my current tank inhabitants are suitable tank mates for these morays. The puffers range in size from 1-4 inches.
<I suspect there might well be trouble with the Puffers both biting these tiny eels and consuming all their food. I would at least put a serious barrier/divider between the front and back of a section of your tank to keep them separated>
I look forwards to hearing your reply!
Many thanks,
Kris Graff
<Be chatting. Bob Fenner>

Re: freshwater morays
Hi Bob,
Thanks for the info and the quick reply!
I was wondering if it would be an option to grow the eels on in a species tank and then introduce them to the main brackish tank with the puffers when they are at a decent size. Would I still see problems here as regards to the eels catching food?
<Possibly... the Puffers might be able to be trained to accept food in one corner, the eels the other...>
I will send you some pictures of the eels as soon as possible. My friend has three of different colour phases, the white is indeed very attractive.
Once again, thank you for your help,
Kris
<Be chatting my friend. Bob Fenner>

Freshwater Eel?
Hi..!
<Hi, Carlos... Anthony Calfo in your service>
A few days ago I got an eel, searching at the web found is just one alike and is called lycodontis tile eel, is just exactly the same I have but I'm not sure if it is a snowflake eel (?).
<no sir... you have a variegated "freshwater eel", which favors brackish water and if kept in freshwater may be stressed not to feed... but not a snowflake moray eel>
This is now 6 inches, small but healthy as I think, it open its mouth sometimes when quite in a place and moves greatly but feeding is kind of concern, since 4 days ago never seen it eating, I tried freeze dried blood worms,
<good food, but not likely to be taken>
fish flakes ( as pet shop owner recommended) a <that person needs a good book... the only way that eel is going to eat flakes is with a slingshot>
and now after more research I set a toothpick with beef heart with just small bites on it but not sure if they were from the eel.
<hmmm... perhaps>
What do you recommend about this situation?
<try crustaceans (live and frozen)... krill (FD and Frozen maybe)... live ghost/grass shrimp very good>
my eel is moving and breathing as usual so I think is healthy, color, eyes and dorsal fin ( from head to tail) is ok.
<excellent>
What kind of eel is this one.? probably it just eat live fish and need to try. Best regards.
<live fish not necessary, I believe. keep us posted, Anthony>

Eel food..?
Hi..!
searching on your site I found my eel is just the same as: Gymnothorax polyuranodon .
<excellent, Carlos... but that is a good stretch from the tile eel species mentioned in your first e-mail. The feeding advice stays the same... but did you buy the eel in fresh or saltwater. If saltwater, disregard the history mentioned in the last e-mail. Best of luck to you, Anthony>
Thanks.!
Attn. Carlos Gorgon

Just got a "freshwater snowflake eel"
Ok at the risk of sounding like an idiot...I just got an eel...the guy I bought it from said it was a freshwater moray snowflake eel, he seemed to know what he was talking about and was fairly helpful...the eel is about 6-8 inches long and in a 10 gallon tank... water is entirely fresh and clean...I got some frozen silversides from the guy I got the eel from and was wondering if this is a good food for him? I threw a few in there, about an inch square cut from the package, I let it thaw and then dropped them in front of his hiding place (a plastic decorative aqua-gator with hollow belly and mouth open) he didn't move for them...I have fish gravel rocks on the bottom and a filter that I got from Wal-mart...I guess I just need to know exactly what steps I need to take to make this a happy healthy eel that isn't going to die on my fiancé.....she will be crushed....please help me....I know that all this is probably in the FAQ but I wanted it personally...if you could send a reply to my e-mail address I would be extremely grateful....thanks a lot.....Mike
<you are correct my friend. There is so much to say, and at times we are pressed so dearly for time to try to keep up with e-mailed queries that restating covered topics can be difficult. The eel species needs to be ID first as a true fresh, brackish or marine species. The 10 gallon tank is obscenely small whatever it is. Diet will depend o species again, but is likely to include crustacea (live shrimp (ghost/grass), crayfish, krill, cocktail shrimp frozen). If it seems to respire fast it may need salted water indeed. Please browse articles and FAQs starting here: http://www.wetwebmedia.com/FWSubWebIndex/fwmorayeels.htm
Best regards, Anthony>

Freshwater moray eels... actually brackish 11/18/05
Hi-
I have a 180 gal. tank that I've had for a long time. My fish have been thriving for many many years. Three years ago I felt really sorry for two "freshwater" moray eels in a shop in a tiny tank. They looked terrified and had no shelter. I know from scuba diving that they like to stay in caves or overhangs and I could tell these guys were miserable and terrified. I went ahead and bought both of them, then went on the internet to see just what I needed to do for them. I upped the salt in my tank to one tablespoon to 5 gallons. My other fish are doing fine after three years. I have Jurupari, one mono, and one "fat" goby. So the eels have been great and happy-- they each have their own cave, they were eating calamari, shrimp, krill, salmon and smelt.
<Me too!>
I know they can go a few weeks without food, which they do sometimes. They are off the food again. The problem is that for the last two and a half MONTHS they haven't eaten, they go into one cave together (which they NEVER would have done before), one has a swollen throat, the other has a lump on his chin,
<Likely goiters... from a lack of iodine (can, should be administered exogenously) and the cumulative effects of life in too "fresh" water>
and they are just acting very strange. The goby is looking grayish (he's a dark brown normally) and his eyes are a little cloudy. The eels and the goby won't eat and the other fish seem to be ok. The water tests are all fine. I've upped the salt to one tablespoon to two and a half gallons of water and upped the temp to eighty five. A week later, they still don't look good. If you can help me with this I would appreciate it greatly.
Also, do you know how long "freshwater eels" live?
<Years when kept in brackish (spg of 1.005-1010) to marine (as adults) water>
Thank you very much—
Dana Mardaga.
<Bob Fenner>

"Freshwater" moray eel (03/11/03)
Hi, my name is Nate and I've had a "freshwater" moray now for about six or seven months.
<Hi -- Ananda here, seeing those quotes around "freshwater" and hoping you do indeed have it in brackish water...>
He ate very vigorously for about six and a half months, now he will not eat. I read a lot on the internet about them and their feeding habits, and it's has only been about three weeks since he last ate.
<Do also check our articles/FAQs on these fish: http://www.wetwebmedia.com/fwmorayeels.htm and http://www.wetwebmedia.com/fwmorayfaqs.htm>
That's not my main concern though; he now has developed white splotches on one side of his body near his tail. The water has been tested and seemed to be completely fine. If you have any idea or advice it would be greatly appreciated.
Thank You.
<Could be a number of things. Without specific numbers for any of your water quality parameters, or more info about the tank, it's impossible to be certain what the problem is. I would do a water change on general principle, and perhaps change the tank salinity a bit. Do look for photos of ich and compare to what's on your fish. If you have ich, check the WetWebMedia site for treatment info. If it isn't ich, a photo and detailed tank and water quality stats would help us ID the problem. --Ananda>

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