Marigold swordtail and guppy fry  10/7/08
I have a 30 gallon tank which is currently holding about 15 mixed guppy's and marigold swordtail fry, then a 46 gallon tank in the basement with about 75 marigold swordtail fry. They are about 6 to 7 months old. Some of the guppies look pregnant already, and the original tank which held the parents seem to have yet another swordtail and guppy that are pregnant. I have them both in a breeding cup. I have been extremely successful with swordtail births in the breeding container before as well as the guppies. I originally started with about 6 fish. I need to know if it's possible for the fry to be pregnant already...how can I tell the swordtails apart male from female, and should the siblings be separated? I have well over 100 fry living from the original 6 fish...HELP
Donna
<Donna, the short answer is you can't magically make the males stay away from the females. As soon as they are sexually mature they will attempt to mate with any females they have access to. The normal way to breed livebearers is this: you remove the fertilised female to another tank where she can release her fry safely. After she gives birth you put her back in the community tank. In the meantime you watch the fry develop. After two months, and before three months, the males will be sexually mature, so that is your deadline for observing them and then removing them to a tank of just males. Eventually you will end up with all the males in one tank, and all the (virgin) females in the other. If you don't have two tanks for the juvenile fish, then use a tank divider to split the tank into two halves, one for the males, and one for the females. Within 3-4 months, the fish should be big enough to sell or give to other hobbyists. Simple as that. Cheers, Neale.>

Re: marigold swordtail and guppy fry – 10/07/08
I understand most of what you said but I am having trouble in the 46 gallon, telling the males apart from the females.
<Pretty easy... look at the anal fin; on male livebearers, the anal fin is tubular and bent over into a rod-like structure. Since the males start of with triangular anal fins like the females when young, you can tell they're sexually mature once their anal fins change shape.>
The original tank upstairs, has two males that have a long black straight sword tail.
<Irrelevant to sex determination. While it's nice that male swordtails have big tail fins, you absolutely cannot rely on this to sex them, because this structure won't be obvious (if present at all) on young males.>
They have created all this!!!? I can't see this black sword on any of the males in the basement. Not one of them show the black mark.
<Forget about it. Concentration on the anal fin.>
Could I have 70+ females?? They are over 6 months old, should I be able to tell the males from females at this point???
<Yes; the males will have obviously modified anal fins.>
The guppies are separated in the dining room and some of the fry are already pregnant but at least I can tell which ones are the males.
<Cheers, Neale.>

Re: Molly, Platy crosses... 8/30/08  9/17/08
Hi Neale,
<Jenna,>
Thanks for your reply to my original question about mollies and platies cross breeding! I have finally motivated myself to get a few images of the fry I ask about, though the lighting in here is terrible and good images are very hard to get!
<Oh.>
I have attached a couple of images of the two lyretailed mollies I have (both male and the only mollies in the tank) and the only 2 clear(ish) shots of the fry that I managed to get. Also, here is a link to a YouTube clip of some of them
http://www.youtube.com/watch?v=plssSOrfvRI
<All look very healthy (and your cat sounded mighty interested, or hungry).>
The fry are growing well and the mothers are almost ready to drop the next batch. Even though the fry have platy mothers with vivid red, white, blue/green, black and white colourings, the fry have the yellow and black colouring of the mollies.
<Interesting.>
So now how does it look? Do I have freak cross bred fishies or am I as horribly confused about it as I feel?
<These look like regular Mollies. The complicated thing is this: both Mollies and Platies can store batches of embryos, so you can move a female to another tank without males, and then she produces fry some months later, the result of a mating that might have happened anything up to six months later. It's also difficult to sex some of the fancy livebearers because modifications to the anal and pelvic fins obscure the basic anatomy. The fish in the photo labeled "matydaddy2" for example might look like a male, but it's almost certainly a female. The anal fin is large and triangular, though the two extended pelvic fins could be mistake for the gonopodium. Consequently my assumption is that the juvenile fish are her offspring. Mollies are sexed by looking at the anal fin: on females it has the normal shape, on males it is crooked, and bent over into a tubular structure that looks a bit like a stick.>
Thanks heaps,
Jenna
<Hope this helps, Neale.>

Living with expecting tank mates and other questions : Marbled Mollies, Hi-Fin Tetras, Platys and a Loach    9/6/08
Hello, I am new to the site, and I have read many of the posts which have really helped me get to know my new fish! I do however have a few questions in relation to my personal situation. I have a 29 gal tank that housed multiple Goldfish from March to July 08'. I kept my albino weather loach,(Golden Dojo) in the tank as she is quite calm and gets along with anything. I have even kept her with snails,(which they eat in the wild) and she never even nudged them!
<All sounds nice.>
She also keeps my tank clean and I prefer her to an algae eater,(catfish.)
<Agreed; a better combination for the coldwater tank.>
I have a three-piece "Sunken Pirate Ship" which is rather large and provides excellent hiding spots for the fish! In fact, the Dojo sleeps in the middle portion of the ship every night. I also have one live plant which I am not sure of its name. I purchased it as a dry bulb and it has grown in the tank which is next to a window,(at least half of the tank gets sunlight everyday.) I also have a rather large, fake, "plant" which I keep at the top of the tank, half in the water. I have a water heater which is recommended for a 30-60gal tank, and it seems to keep the water around 74-78 degrees.
<Slightly on the warm side for both these species; scale back to 20 C/68 F and you'll be in the "sweet spot" for Weather Loaches and Goldfish. At warmer temperatures, you're more likely to cause/experience problems than otherwise.>
I also have one long bubble wand in the back of the tank, and bubble "toys" at each front corner of the tank. The Dojo likes to lay on the long wand and swim through the bubbles! I also have a large double filter designed for a 30-60 gal tank, and a small single filter for a 5-15 gal tank that I use to help get the tank clear after I clean the rocks and cycle the water.
<All sounds great; where Goldfish are concerned, "super-sizing" your filtration system is always a good move, and I'd argue essential for long-term success.>
Anyway, now to my question. After I took the Goldfish out of the tank, I let just the Dojo live in the tank for about two weeks while I treated the water and cleaned the tank, cycling the water every few days. We had an issue with a parasite in the water before and I wanted to make sure everything was clean,(the Goldfish had a thick slime-coating all over, and slight fin-rot.) I thoroughly cleaned my "Pirate Ship" and all of the toys, rocks, plants and the tank itself before introducing new fish.
<Do understand that excess slime production and Finrot are both symptoms of water quality or water chemistry issues. They don't "come out of the blue" for no reason. So, check the nitrite level, to ensure the water is clean, and check the pH, to make sure it is stable around 7.5.>
My Dojo never had any signs of illness, but I also treated the water with Melafix, Ick Cure and Salt even after I moved the Goldfish, just to be sure.
<Well, Melafix is largely useless, and Ick Cure is redundant and arguably dangerous when used randomly. Ick medications contain copper, and copper is toxic to fish. We use them on the basis that the copper dosage will kill the parasites before it kills the fish, but be under no illusions that the copper is bad for the fish even so. Hence you should never use medications unless you have an express reason to do so. Do always remove carbon when using medications, otherwise they don't work reliably, if at all.>
Around two weeks ago, after all signs of the "slime" were gone or cleaned, I decided to add a few fish in with the Dojo. I purchased 3 Black Mollies,(2 marbled females and one black male.) 2 Platys,(1 male and 1 female.) and 2 Hi-Fin Tetras,(not sure of the sexes.) I have been adding API Stress Coat to ease them into their new environment, and I add API Aquarium Salt to ensure healthy fish and water.
<Not a good combination for several reasons. Did you read up on the requirements of these fish? Mollies must have very warm water, 26-28C/78-82F, preferably with salt added at a dose of 3-6 grammes per litre. Such conditions will be too warm for the Weather Loach. The usual Hi-Fin Tetra is a species called Gymnocorymbus ternetzi, a notorious fin-nipper. Mixing with Platies and Mollies, which move quite slowly, is asking for trouble.>
I read that all the fish in my aquarium like a little salt in their water, but not a full marine environment.
<Tetras can't bear salt; they come from soft water habitats, so adding salt to the water is stressing them. Mollies demand *marine salt mix* not that "aquarium salt" guff retailers will try and push on you. This "aquarium salt" is just table salt and doesn't raise the pH or hardness, so won't help the Mollies much. Platies don't mind a little salt, and will be fine at 3-6 g/litre. Loaches don't want salt, so again, they're being stressed in the long term. Please realise adding salt in "teaspoon per gallon" doses has no basis in science. It's something inexperienced aquarists get told about, and because its cheap, they do it. But you will do a lot better skipping tonic salt and concentrating on what water chemistry your fish actually need.>
Everything was going fine. I had wondered if the Dojo would get along with the new fish, and she hasn't even looked in their direction so far. The new fish don't seem to be scared or intimidated by her at all, so I think all is well with their new tank-mate!
<Ok>
Here is where I need advice. Around the 1st of Sept. I noticed that the new females,(there are three, 2 marbled Mollies and an Orange and black Platy.) All look swollen and pregnant! I had anticipated this, but didn't realize it would happen so quickly! One of the Mollies likes to lay her bulging belly on top of the heater!
<Dangerous: she can easily become burned doing this.>
The other Molly likes to hide with the male in the big mass of plants on the top of the tank while the Platy just hides in one of the Pirate ship sections and sticks with the male when she's out eating and mingling. To my surprise, all the females actually seem to take a dominant role !
<The female certainly isn't "hiding with the male"! Be sure to think like a fish, not like a human. Mollies don't have pair bonds. The male is staying with the female because he wants to mate with her. He'll as soon eat her babies as anything else, so there's nothing nice going on here.>
Anyway, I wanted to know what you would do in this situation. Should I separate the females from the males now?
<If you want to rear the babies, then yes, moving the females into another tank is a good idea. Scoop them with a jar, not a net, so you don't press their bodies and damage the babies inside them.>
Do the females also need to be separated from each other?
<No.>
I have another 29 gal.. tank, but it isn't set up and I don't even have a filter for it yet! How long will it be before the fish give birth?
<Gestation period is around 1 month.>
If I purchased a small 10gal tank and set it up, would it be aged enough for the fry when they arrive?
<Yes.>
What about breeder nets?
<Waste of money.>
Can all of the fry be kept together once they are born?
<Yes.>
What do I need to feed the fry?
<Algae and finely powdered flake food.>
Also, and most importantly, what can I do to make sure that the Moms are comfortable, and live through the birthing process!
<She'll be fine. Again, think outside the human experience. Fish don't have a pelvis like a human, so there's no bones in the way of the birth canal. The babies slip right out, no stress or discomfort. Mollies do miscarry when stressed, but that's something else. Usually caused by males pestering them or by aquarists putting them in nets or breeding traps.>
Do fish usually live or die during/after birth?
<Your Mollies will fine, and looked after properly will have many broods across their ~5 year life span.>
I have a 6yr old Son whom enjoys helping me take care of the fish, and he'll be crushed if something happens to the Moms! He is thrilled at the prospect of new baby fish right now, but I need to prepare him for the death of the Moms if it is a common occurrence!
<It's not. Mollies normally die because people put them in freshwater tanks with freshwater fish. They get Finrot and Fungus. But breeding isn't an issue.>
At the moment, I do not have any ph, nitrate, or ammonia levels for you as I have never used the kits before. I hope you can give me some good ideas as I plan on giving the fry every chance for survival!
<Please do read our articles on Mollies and Livebearing fish generally:
http://www.wetwebmedia.com/FWSubWebIndex/poeciliids.htm
http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm
Mollies can be kept in freshwater rather than brackish water, but it's an uphill struggle because the pH must be high (7.5-8.2), the hardness as high as practical, and the water quality 100% perfect all the time. I'd honestly recommend setting up a brackish water tank just for your Mollies. Fill with suitable floating plants and you should be able to rescue at least some every month. Put the babies in a breeding net for 6 weeks, at which point they'll be big enough to be turned loose in the main tank.>
I thank you in advance because I think what you are doing for these people/fish is a great thing. I remember how helpless I felt when I started my first tank, and here I am again with my first "live bearers." Often you feel as if you have nowhere to turn, and its hard to find people to help you when you really need it! I had an issue with a Black Moore earlier in the year, and my plea for help went unanswered on another site! The Black Moore died, and I found out later that she just needed a few green peas to ease her digestion!
<Quite so.>
Fish, like so many creatures, cannot speak for themselves. It is up to caring, responsible individuals to look after their needs and treat them humanly! Personally, I think the traditional "round Gold-Fish bowl" should be outlawed! I personally stopped a group of teenagers from buying one of these "death traps" just last week!
<Well done!>
I commend you for your selfless quest to help the fish of the world!
Anecia
<Very kind of you to say so. Cheers, Neale.>

Re: Living with expecting tank mates and other questions : Marbled Mollies, Hi-Fin Tetras, Platys and a Loach – 09/07/08
Hello Neale, and thank you for such a timely response! It is nice to know that someone is there to help you when you feel helpless. As for my own experiences, I have learned that it is better to avoid obvious mishaps when it comes to fish, and I am going to take your advice and correct my mistakes!
<We are happy to help.>
First of all, I cannot believe the pet store sold me these fish knowing they needed different water needs,(fresh vs. marine!)
<Actually a common mistake. Mollies can be kept in freshwater tanks (they certainly don't need a marine tank). It's just they're not very hardy, and 50% of the time (no kidding) they get sick. In brackish water, by contrast, they're practically bullet proof. And in marine tanks, the same. It's a contentious and complicated issue why this is, and whether or not they can be kept 100% healthily in freshwater tanks. Some argue not (like me) others argue it is possible, provided you obey the key rules (possibly true, but impractical for casual aquarists).>
From what I can see, my Loach and Hi-Fin Tetras need to be in a freshwater tank, and the temp needs to be considerably cooler than the Mollie/Platy tank, right?
<Platies are fine in coolish water, around 22-24 C (that's 72-75 F) will suit them well, and will work nicely with Weather Loaches. The Gymnocorymbus will be fine in that too. It's a common mistake to keep South American tetras too warm; Neons for example like quite cool conditions, and "burn out" if kept warmer than 25 C/77 F. It's really just the Mollies that don't like cool conditions. They're very much "hothouse flowers" and thrive at balmy temperatures many other fish don't care for so much.>
I went out and bought a 10 gal tank last night, and, as I mentioned, I already have a single, 5-15gal filter, which I have already been using for at least a few months. If I use this filter in the new 10gal tank, will that prevent "new-tank" syndrome? How long should I wait before moving the fish into the new tank?
<Moving a mature filter from one tank to another, if done quickly (i.e., within 10-20 minutes of switching the power on/off) works extremely well. However, the water chemistry between the tanks should be the same; at an extreme, taking a filter from a saltwater tank and connecting it to a freshwater aquarium won't work. Try also to minimise temperature differences; doesn't need to be exactly the same, but keep the difference to within a couple of degrees. You can also move filter media, taking up to 50% from a mature filter and putting it into the new filter.>
The new tank can go marine or freshwater right now.
<The marine tank? Do you mean a saltwater tank with corals and whatnot, or a tank that's had a little salt added but contains freshwater fish?>
I will definitely separate the loach and tetras from the Mollies and Platys, but which should I move to the new tank?
<Mollies certainly need a 29 gallon tank minimum, and I'd not keep them in anything less than a 20 gallon tank in the short term. They are sensitive to water quality issues for a start, but they're also big, active, and by community fish standards, quite aggressive (the males anyway).>
My 29gal tank was the one that I put the "Aquarium Salt" in, but you said that it probably isn't helping anyway, so I could easily revert back to freshwater.
<Absolutely.>
On the other hand, should I move the Loach and Tetras into the small tank, and let the 29gal tank be the marine tank with the Mollies and their new fry? Your call.
<I'm not wild about putting either Loaches or Tetras in tanks smaller than 20 gallons to be honest, so it's six of one, half a dozen of the other. For now, I'd look at the size of the fish you have, and act accordingly, bearing in mind some of these fish will grow and may need different quarters in the long run.>
I bought a small heater for the 5-10 gal tank. Will this be adequate?
<Can't possibly tell from here! Depends on the temperature of your home for a start. Try it out and see. If the heater is constantly on but the tank stays cool, it's likely underpowered for the job.>
I was thinking it would be for the Loach/Tetras since they do not need a very warm environment. From what I can tell, the Tetras and Loach will be stressed will the salt, and I am afraid they might take it out on the slow-moving Mollies, so I need to separate them soon!
<You may be fine with your Gymnocorymbus; some people report no problems with them in community tanks. I'm just telling you what sometimes happens, so that you're prepared.>
Also, I need to purchase the right kind of salt for the Mollies. What should I ask my retailer for, and is it sold in some of the larger retail stores,(IE: Wal-Mart, etc..) If the general aquarium salt I bought isn't doing any good, then the Mollies need help right away!
<What you're after (ideally) is the salt used in marine tanks. Many brands: Instant Ocean, Reef Crystals, etc. They're all fine for this. Buy whichever is cheapest. All you need do is add 3-6 grammes per litre of water (0.5-0.8 oz per US gal) in each new bucket of water. Stir well, and when the salt has dissolved, pour it in. All livebearers will tolerate this level of salt, so you can keep Guppies, Swordtails, Platies and Mollies all happily in this as you wish. They will be hardier and healthier.>
Also, thank you for clearing up any misconceptions I might have had about Melafix, and Ick Cure. I won't use them again without consulting a professional!
<It's not so much we're professionals, as we're not trying to sell you anything -- and that's the difference. Some stuff is essential in life, but other things... not so much. In the long run, it pays to know what you need and when to use it.>
Again, some of these pet stores just don't care what they sell!
<The operative word is "some". There are many excellent pet stores, often the "mom and pop" places where the managers are hobbyists themselves. But even so, it's like buying a car or a computer -- the salesman will have an angle he's trying to push, and you need to have done your research so you know which questions to ask and which sales ploys to avoid. Spending $10 on a basic aquarium book is money VERY WELL SPENT. Bob and I have put together a list of our favourites, here:
http://www.wetwebmedia.com/FWSubWebIndex/bookswwmsugg.htm
Have a nose around, and see if your local library or bookstore has these volumes. If you click the Amazon links, check to see if you can buy the book Used; that'll save you more than a few pennies.>
Anyway, one of the two sets should be moved right away to accommodate their needs,( either the 3Mollies/2Platys or the 2Tetras/1Loach. ) Please advise me as to what you would do in this situation!
<I'd keep the Platies and Mollies together as a Livebearer system; you can become a "specialist" with that tank and learn about them and breed them as you wish. Put the other fish in the (slightly cool) tropical tank at 22-24C, and if you add other fish, be sure that you check they'll be happy under such conditions. Many fish -- such as Danios and Corydoras -- absolutely LOVE slightly cool conditions. But there are a few, like Gouramis and Angels, that aren't so keen.>
I have noticed that the male Platy doesn't seem to like the Mollies very much. Do these species live together well?
<Males of most livebearer species are mutually aggressive. Keep the tank spacious and stock with floating plants and/or tall plastic plants and they'll coexist up to a point. But this is why I repeatedly make the point here and in magazines -- livebearers aren't "just add water" easy fish! They are demanding in their way, and also very rewarding once you get everything right.>
I have another 29gal tank, and I am planning on setting it up soon. I might move the Platys into it, and let the Mollies and their new fry have a tank all to themselves!
<Sounds great. But I'd honestly put it to use as your main community tank, and leave the 10 gallon tank for rearing baby fish and putting pregnant females in so they can rest-up away from the males. Giving female fish restful quarters so they can give birth and/or recuperate after laying eggs is a VERY GOOD THING and will get you serious time off Purgatory!>
Also, you are right about the male Mollie pestering the females. There is one female that he stays with all the time, and she gets aggravated and makes him go away! Will he always pester her, or will things get better when the fry mature? I suppose its better to have a lot of females and only 1 or two males! Correct?
<Correct; 2 females to 1 male is the baseline, but the more females the better. You'll soon have her daughters so I wouldn't go buy a bunch of fish now, but one extra female might make all the difference. When you're rearing your fry, sell on all the males and most of the females, but keep a few of the girls for your "swarm" of Mollies so the mothers and daughters can all hang out together.>
I hope everything works out for our new fish, and I am going to do everything I can to make sure they are healthy and happy! Again, thank you for taking the time to help me, I would never have known that I wasn't giving the new fish all they needed to thrive!
Sincerely, Anecia
<Glad you're enjoying your hobby and learning all there is to know! Cheers, Neale.>