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FAQs on the Molly Reproduction 3

Related Articles: Mollies, & Poeciliids: Guppies, Platies, Swordtails, Mollies by Neale Monks, Livebearing Fishes by Bob Fenner,

Related FAQs: Molly Reproduction 1, Molly Reproduction 2, Molly Reproduction 4, Molly Reproduction 5, & Mollies 1, Mollies 2, Molly Identification FAQs, Molly Behavior FAQs, Molly Compatibility FAQs, Molly Selection FAQs, Molly System FAQs, Molly Feeding FAQs, Molly Disease FAQs, Livebearers, Guppies, Platies, Swordtails,

Platy/Mollie crosses 6/30/11
Hey in my community tank I just got a small (young I think) female silver Mollie. I have noticed my Male Red Platy mating with her and no one else is! (3 other males in tank). Can anything come of this?
<Mmm, in the way of progeny? No... there are other possible cross species crosses... Platies w/ Xiphophorus helleri, others... Mollies w/ Guppies, Endler's...>
I would love to see these hybrid fish! Should I take her out to stop any further breeding with other males. Here is a picture of the male.
<Ahh, very nice. Bob Fenner>

Balloon Molly died while giving birth 4/18/11
Hello there,
We have a 47 gallon, tall freshwater fish tank. Inside are (were) 3 adult female balloon molly's, 2 baby balloon molly's that are about 2 months old, and 1 dwarf male Gourami.
<Yikes! Two of the worst species for the casual aquarist. Plus, the water conditions your Mollies need are inimical to what Dwarf Gouramis need. So there's no real likelihood of easily keeping both species healthy in the one aquarium.>
The baby balloon molly's arrived the day after we got our two black ones.
We didn't know what we were doing at that point, but she had 10 babies. 1 was a stillborn, and 7 slowly disappeared as we didn't know about the frequent water changes and our nitrite level suddenly sky rocketed!
<Nitrite, with an "I", as opposed to nitrate with an "a", comes about from poor filtration, not water changes. Understand this: fish excrete ammonia all the time, and then your biological filter processes that to nitrite and finally to nitrate. So in a healthy aquarium you should have zero ammonia and zero nitrite because they're continually being removed, but steadily rising leaves of nitrate because that's the end product of the biological filtration process. Water changes -- 20-25% per week -- dilute the nitrate, and for Mollies in freshwater tanks (which I honestly don't recommend) that nitrate level has to be very low, less than 20 mg/l, and ideally close to zero. In freshwater conditions nitrate is more toxic than in brackish, and Mollies are very sensitive to nitrate, more so than your Gourami, and consequently likely to be harmed by high levels of nitrate. Ammonia and nitrite, by contrast, are dangerous to all fish no matter what the conditions. In the average community tank, levels of 0.5 mg/l ammonia and 1.0 mg/l nitrite are potentially lethal. Anything above zero is definitely not safe. If you don't have zero levels of these two chemicals, then you have either [a] too many fish; [b] too little filtration; or [c] you're feeding them too much. Oftentimes it's a combination of the three.>
We did a couple water changes to get the nitrite level back to about 0 and are feeding them less since we found a great deal of food at the bottom of the tank when cleaning the gravel.
<Nitrite won't be permanently pulled back to zero by water changes because it's continually being produced by your filter as the bacteria process ammonia produced by your fish. It's crucial you understand this. You MUST remedy the problems with your filter and/or reduce the stocking level and/or reduce the amount of food you're giving them.>
Yesterday around 4pm I noticed the third balloon molly, who is orange, suddenly sitting at the bottom of the tank. She had two growths that looked like little bubbles on her behind which made us think she was in labor. We had a male in the tank about a month ago, but died shortly after. We believe he impregnated at least the one. Our heater broke so we had just gotten a new one the other day to keep it at a warmer temperature for the babies especially.
<Mollies are very sensitive to cold water, but so are Gouramis.>
We do not have a breeder net, but the other fish have left the babies alone and it is a large tank for the number of fish inside. (We plan on getting a breeder net for future babies but this wasn't expected right now). After about an hour, the other fish left the orange balloon molly alone. We turned off the light and the temperature in the tank was between 78 and 79 degrees. As of this morning, she still had not had any babies. She would move all over the bottom of the tank and hide a little, but the other fish were not bothering her.
Around noon today I saw the mother was laying on the bottom of the tank, dead. Those two bubble-looking things are still on her bottom, but we have no idea why she died. I tested the water for everything but ammonia (we haven't gotten any new fish in a few weeks and at that point it was only 1),
<1.0 mg/l ammonia isn't something to scoff at! That's pretty dangerous!>
everything came back normal and safe. Nothing was borderline being dangerous or anything like that.
<Really do need the numbers rather than your interpretations. Let's be clear here. Mollies require water hardness upwards of 15 degrees dH, and a pH above 7.5. Water quality must be ammonia = 0, nitrite = 0, and nitrate less than 20 mg/l. Moving on to the Dwarf Gouramis, these need very soft, acidic water, 1-10 degrees dH, pH 6-7. Again, water quality has to be excellent, 0 ammonia and 0 nitrite. I can't think of any middle ground that would be healthy for both Dwarf Gouramis and Mollies, so keeping them in the same tank is bound to be difficult.>
The last water change was done about 4-5 days ago and we were planning on another soon.
Ich is not in the tank and all the fish are acting perfectly normal. Did we do something wrong to cause her to die? We've had her since about February of this year. She was fine up until yesterday when we thought she was going to have her babies.
Thank you for your help.
<Trisha, the bottom line here, I suspect, is you've bought fish that you really don't have the skills or set-up to keep. Mollies are not easy fish to maintain, and many people find them impossible to keep in the long term.
Those are usually people who refuse to set up tanks catering to the needs of Mollies, i.e., hard, alkaline, and ideally slightly brackish water. Of course adding salt isn't an option here because salt would stress your Dwarf Gourami, and they're flimsy enough already without being stressed further. Do help yourself by doing some more reading, and pay particular attention to the needs of Mollies and Dwarf Gouramis, and the proper way to set-up and maintain an aquarium.
Hope this helps and good luck, Neale>

Small male Molly attempting to have sex with larger Sailfin Molly-- 03/20/11
Hello, and thank you for taking time to hopefully enlighten me on a curious behavior one of my young male mollies is displaying. Three days ago, I brought home a couple of female(ready to pop with fry) female Dalmatians, <Best not to move livebearers close to parturition>
and one big beautiful male Sailfin Molly. I added them to my 50 gallon tank that includes 5 Silver Dollars,
<Mmm, these Characins "like" very different water quality than mollies (soft, acidic, warmer vs...)... Not compatible>
2 little Algae Eaters,
<Hopefully not Gyrinocheilus... see WWM re>
and 1 "teen" female/2 "teen" male Dalmatian Lyretail Mollies. An interesting behavior has begun with one of my "teen" males, as he following, and checking out the under belly of the big male Sailfin.
<Mmm, actually not uncommon>
Of course, the big male seems annoyed, and swims in a circle with his sail up in full grand display, but the youth male seems undeterred, and has now gone to chasing and jamming his gonopodium fin into, or AT least at the "right" place of the Sailfin. What I cannot understand is "why". I KNOW why with a female, but doesn't he know after "checking" that this is another male? He checks, and then he tries to mate.
Any help you can offer on the subject would be great! One additional question you can hopefully hit the "easy button" for.. Is it possible for what appears to be a female molly as a larger fry to turn into a male after further maturity? In other words, can a molly change sexes as they develop?
<Mmm, yes>
Again. Thanks so much, and I really appreciate your site!
Kind Regards,
Abbi S.
<Thank you for sharing. Bob Fenner>

Poecilia sphenops; lack of babies, and the importance of Indian Fern 1/14/11
I bought a ten gallon tank a few months ago with the intent of breeding mollies. When my fish started having babies I bought a 70 gallon tank to keep the adults in and continue to keep the babies in the ten gallon. The problem I am having is that I have had six batches of babies from six females but I have had no babies since. I have six females in with two males and the females don't seem to be getting pregnant. I put them all on a calendar knowing that they should have babies approximately once a month but all my females should have had babies over a month ago and none of them are even pregnant. Why aren't my mollies mating?
<Your fish almost certainly are mating. You just aren't seeing any fry. In the wild Mollies live in thickly vegetated canals and ponds. Immediately after they are born the fry hide among floating plants. That's their
instinct. Because they're well hidden, the parents don't see them. And because the fry are basically fully-functional miniature Mollies, the parents don't have to look after them. Together these things mean that
adult Mollies evolved with no instinct to protect their offspring. They simply don't see their offspring in the wild very often, and don't need to recognise them even if they do. So when adult Mollies see baby Mollies, they don't see offspring that need care or at least should be left along -- they see wriggly little edible things much like mosquito larvae! It's absolutely essential you stock the Molly aquarium with floating plants -- Floating Indian Fern is by far the best choice, and worth getting mail order if it isn't sold locally. You will quickly find baby Mollies hiding among the floating plants. Scoop them into a breeding trap, rear them there for 3-4 weeks, and by the time they're about an inch long, they'll be immune to attack from the adults and can be turned loose. Cheers, Neale.>

Baby Mollies 12/17/10
I brought a new tank around 2-3 months ago and with it brought some Dalmatian mollies, I had a tank before but wanted to try a tropical tank.
Anyway 2 days after I got my mollies one of them had babies. I put them in a separate tank to protect them and they have flourished, I only had 19 babies altogether a few of them died, I now have 6 big, beautiful spotty babies about 2 months old, they are in the bigger tank now with the others but I was trying to find out what sort of age they will start trying to breed? I can't find it anywhere!
Can you please help!
I have attached a photo of one of my big babies, I'm so proud of them!
Many Thanks
Also I have one smaller baby left in my breeding tank, he has always been smaller than the rest but since being alone he hasn't caught up in size at all, I feed him regularly and have tried changing 50% water change but nothing really seems to make a difference, he's very active and swims up to the top when he knows its feeding time but he just doesn't seem to be getting any bigger, I feed him normal fish flakes and also occasionally spoil him with cut up blood worm.
If you have any advice to help me bulk up a little it would be greatly appreciated.
Many Thanks again
<Hello Tania, and well done rearing your baby fish! Male Mollies become sexually capable within 2-3 months, females slightly later, perhaps 3 months on the average. If you're trying to keep your females "virgins" for the purposes of subsequent breeding, then it's a good idea to remove males from the batch as soon as you can sex them, i.e., their anal fin adopts the characteristic stick shape that allows the males to direct sperm into the female. The fish in your photo appears to be a female, and has the typical triangular anal fin typical of female Poeciliidae. As for baby that don't seem to grow, that's not unusual. Because Mollies are inbred to create the bright coloured forms many people prefer, runts are common, as are
deformities of all kinds, from crooked spines to inadequate swim bladders.
There's not much to be done with such specimens, though euthanasia may well be appropriate in cases where the fish is suffering or you don't want those "bad" genes passed along to the next batch of fish. A litre of aquarium water will 30 drops of clove oil will euthanise small fish quickly and painlessly. Do read about Mollies here:
Cheers, Neale.>

Re: New Balloon Mollies 9/7/2010
Thank you for all your help however the very next morning, I found my guppy dead, and I was relieved I did not have to make any euthanasia decisions.
I just brought home 2 balloon Mollies yesterday. Bad mistake, I should of taken only one. I put these 2 together in a 5 gal tank temporarily as I know they will eventually need a bigger tank.
<Indeed. Mollies are not easy fish to keep.
Lots of people have problems with their water chemistry and water quality requirements, as well as the aggression commonly exhibited by males.>
However although I was told they were both males.
<Why did you need to be told they were males? Males and females are easily distinguished. Females have triangular anal fins, while the males have anal fins bent into a tube-shaped structure called a gonopodium that functions as a sort of penis, for injecting sperm into the female.>
I am seeing some tiny looking tad poles, which I am assuming are fry?
<Very likely.>
I am sure none will survive as I have been told that the parents will eat their own fry.
<Not necessarily. In tanks with floating plants there's a good chance the fry will thrive.>
However, I was wondering if they did not get eaten would it be possible for them to survive on the few flakes that fall to the ground during a normal feeding?
<Yes, especially if you finely crush some of the flakes.>
Or should I just conclude these fry will not live?
<Far from it.>
Now I would like to separate the 2 but I need to be sure which one is the male. One is huge, very square, and funny shaped with fanned fins, the other is just the opposite quite small and very round like a bumble bee. Will I eventually notice the male fish chasing the female?
<Males do usually tend to be aggressive, and unlike well-mannered gentlemen, they tend to harass all females, all the time, even if those females are juveniles or already pregnant. This causes a lot of stress on the females, which is one reason why Mollies need big tanks, floating plants for shelter, and above all else a ratio of at least two females per male, so no single female is being harassed all the time. I'm not a female of my species, but I have to imaging being trapped in a small box with a male that constantly tries to have sex with me is pretty unpleasant. So you'll see everything I write about livebearing fish like Mollies and Guppies states again and again how important it is to think about the females and what they need to stay happy.>
What signs should I look for, as I have never had a female fish before?
<See above.>
For all I know these could both be females that came from the store already pregnant.
<Almost certainly the case if the pet shop had males and females in the same tank. Females can also delay the development of some fertilised eggs, allowing them to produce several broods per mating.>
Once again I appreciate any advice you could give me.
<Glad to help.>
<Cheers, Neale.>

Baby Mollies 7/11/10
<Hello Danielle,>
I have a few questions about my Mollies. I have a 4 foot tank I think it is about 120 litres. I also have a 2 foot tank at approx 50 litres and recently I got a spare tank for babies and as a general spare for diseases and injuries etc. They are all filtered, heated and all have nicely cycled water which is lightly salted and all my fish have been doing very well.
1 Pleco
1 catfish
<Could be anything, some species of which get bigger and heavier than the average man! But if the popular little Corydoras, then this poor loner should be in a group of at least 5 specimens; it's not kind to keep them otherwise.>
7 neon tetras
5 cherry barbs
2 sharks
<Don't always get on.>
2 goldfish
2 robin gouramis
<Does prefer warmer water to the other things listed thus far.>
and 7 mollies - mixed black, white and Dalmatian - 2 are boys
<I see.>
recently I noticed one of the mollies had patches of what looks like dead skin on her the others seemed fine so I removed her to the smallest tank and added king British anti fungus treatment. I kept a close eye on the rest and there has been no sign of the flakey skin on the others although the original Molly has passed. I just want to make sure I gave her the correct treatment in case it wasn't a fungus.
<Black Mollies especially display excess slime as off-white to grey patches without any obvious texture beyond that of the scales themselves. Sometimes this is merely a reaction to poor environmental conditions, as with slime
patches on Black Moors. But more often it's a sign of Ichthyobodo, or "Slime Disease", formerly known as Costia. It's easy enough to eliminate by moving the Mollies into mid-salinity brackish or saltwater conditions.
Otherwise medicate as per Slime Disease.>
Also since then I have found 1 single baby black Molly who I immediately removed to the medium tank until he grows a bit. I'm not sure how old he is but he looks like a miniature version of his parents and is about 1cm long
he is fine eating crushed flake food and the odd daphnia and blood worm.
Yesterday my female Dalmatian Molly had babies in the breeding box - I have been told about Mollie fertility so I have a breeding box and a breeding net for emergencies - I removed the babies - approx 40 - and put them in
the small tank - with fresh cycled water - I also removed the filter because it was sucking up the babies. Anyway last night I could see around 8 of the babies moving every so often but they spent most of their time playing dead. What I need to know is how long or if they are supposed to be moving around more because most of the time they look dead.
<Healthy fry will be mobile and active IMMEDIATELY after they are born.
They may not want to eat for a few hours, but they will be swimming actively at the surface. Healthy fry have NO problems avoiding reasonable filtration systems for breeding tanks, e.g., sponge filters or small internal canister filters. Yours sound like miscarriages, which is VERY common when people put adult Mollies in breeding traps. DO NOT DO THIS!
Despite what it says on the packaging, Mollies are severely stressed when trapped that way, and miscarriages are very common. Miscarried fry will sit on the bottom because they're too weak to swim. In theory it may be possible to rear them back to health, particularly if they were almost ready to be born and their yolk sac is mostly gone, but in practise it almost never happens because stress and secondary infections get to them first. Use breeding traps ONLY to house fry, NEVER adults. Instead, use floating plants like Indian Fern as cover for the pregnant females, and then each day look for fry among the leaves and move them into the breeding trap.>
It's like trying to hear a baby breathe and I'm getting quite stressed because I'm worried about them. Are they supposed to be so inactive?
by the way I think this site is wonderful I have never posted before but I have found the information very helpful.
Danielle xxx
I am still new to the aquarium thing - about 6 months -
<Do read:
Hope this is helpful. Cheers, Neale.>

Re: Baby Mollies -- 7/12/10
Dear Neale,
thank you so much for your swift response.
<No problem.>
Since this morning things have moved on considerably. You must be exactly right as all the babies are dead I finally gave in and touched the glass then tapped it ad eventually created a current in the tank with my net and not one movement. I have to assume that they weren't ready which I am surprised at seeing as she was huge.
However, the plot thickens. After moving mum to the netted trap I noticed one of the others was huge too although not as big so I popped her in the trap with a view to shifting her into the smaller tank as I thought if she is due to give birth in a few days then putting her there in plenty of time would be less stressful - this was of course before I read you reply - and while she was in there she had babies!!! these are so different to the others. I wasn't sure you see what they would be like. These babies - there are five - are zipping around the tank quite happily and look so much better. Obviously I know that despite the luck in having healthy babies this time round I need to follow your advice for future and get some of the plants you have suggested.
<Indeed. Moving the female very likely triggered birth, but in this case the babies were ready to go anyway. If the female is only just pregnant, you can be fine moving her and she won't miscarry. If she's about to give birth anyway, then all you've done is induce labour, so to speak. But there's a few weeks in between insemination and birth when she's vulnerable, and if the female Molly is stressed she can deliver embryos with no chance of survival. There's an art to livebearers, which is why those of us who enjoy them are at pains to explain why they're not the "just add water" fish many people imagine.>
I have looked up my catfish - Spot - and he is a Corydoras.
<A Corydoras; two Corydoras. Like sheep.>
I am going to get him some friends as I didn't realise he needed some although he spends a lot of time hanging around the male Dalmatian Mollie - they seem quite friendly.
<He's lonely! Trust me. But a few more *of his species* and he'll soon forget about the Molly.>
The sharks did have a few spats to begin with and I considered rehoming one of them but they settled down quickly and swim happily together now.
<Cool. Can happen, especially if both females I suppose.>
The Robins I got on the advice of a pet store I will not be returning to if they have given me bad advice!
<Robin Gouramis are either a variety of Colisa lalia, the Dwarf Gourami, or a hybrid between that species and the Honey Gourami, Colisa chuna. Both are demanding fish in many ways with a need for warm, soft, acidic water. On
top of that Dwarf Gouramis are plagued with a viral disease. In short, I don't recommend them, and far prefer either Thick-Lipped Gouramis or Banded Gouramis, Colisa labiosa and Colisa fasciata.>
I will need to do some shuffling around with the babies but I will put them into the other tank as soon as the first baby can go in with the new ones and of course check the temperature. Although I have to say they look happy
as Larry.
Thank you again for the advice.
Danielle xxx
<Glad to help. Cheers, Neale.>

Molly fry question 5/26/10
I have a question that I simply am having a very hard time finding any information about.
Long story short, I released some of my black molly fry into the main tank.
I released ten that were between 4 to 6 weeks old. All but one are doing okay and can out-maneuver the adults.
<Floating plants, especially Indian Fern, help dramatically here.>
But, I have one poor fry that was cornered by four adults and partially eaten just a few minutes after release. She is a mess. I managed to scare the adults away before the fry was killed, but she lost a lot of body parts.
<Body parts?>
This fry lost her dorsal fin, most of her tail, maybe 2/3 of the way to the anus, and about 3/4 of her right pectoral fin.
<Fin membranes will grow back, but the muscular part of the "tail" won't.
This fish should be euthanised.
I isolated the fry in a floating breeder tank and the badly damaged tail developed fungus overnight. I immediately bought a 5 gallon tank for isolation and used malachite green to kill off the fungus, which appears to have been successful.
<Malachite Green isn't the usual choice for fungal infections; Methylene Blue is less toxic and more reliable for this.>
The fry is currently in the 5 gallon tank (temperature controlled with filtration) alone save a rock formation to hide under. It's clearly struggling to swim but has kind of figured out how to move around. It appears to be eating, at least a little bit. It's been over three days since the incident and I haven't noticed any significant degradation now
that the fungus is gone.
<I see.>
I plan to leave her in the malachite green for another day or two, then start diluting it with partial water changes. In another week, I'll probably move the smaller healthy fry from the floating breeder to the 5 gallon tank. (Not sure, unlike others, I have actually had pretty good success with the floating breeder tank.)
So finally the question, Is there anything else I can do to improve her chances of survival, and what is the best way to reintroduce her to the main tank?
<If she doesn't have the part of the fish called the caudal peduncle, she's not going to survive, or at least be able to swim about normally.>
I doubt she's much of a threat to even newborn fry because she's very slow, so I planned to wait until she is nearly full grown before relocating her back to the main tank. Advice from anybody with experience raising a crippled fry to maturity would be appreciated.
<Not really much point to this, to be honest. From an ethical perspective, the issue here is quality of life. Without a functional tail, a fish can't swim properly. It can't easily swim away from aggressors, or towards mates, or towards food. If this fry can swim and feed after a fashion, you might decide to maintain her in isolation, but mixing the fry with other types of fish will be fraught with risks. In and of itself, there's nothing you can do "help" a crippled fish beyond removing it from competition and aggression. Cheers, Neale.>
Re: Molly fry question 8/16/2010

Hey Neale,
Thought you would like a follow-up.
<Sure thing.>
This molly is pretty much recovered and has learned to get around pretty well with no tail.
It can even eat off the surface of the water. This fish is going to have some buff pectoral muscles.
<Oh my! I bet he's going to be showing 'em off at Venice Beach before too long'¦>
<Good luck, Neale.>

Molly Fry protection and algae diet 5/4/10
We are brand new to the aquarium world and have just set up our first tank - a 60 gallon (240 litre) salt water tank (4' x 2' x 3') with a live rock reef. It has been running empty for 4 weeks and has now cycled. It is maintained at 26 degrees C (78 deg F) with ammonia 0, nitrite 0, KH 10, nitrate 5, PH 7.8 and salt density at 1.024. We test the levels and use a gravel filter every week and have already completed one 30% water change.
We correct the PH with Reef Buffer as we are trying to get it to stay at 8.4 (recommended by the aquarium supplier) but it always tests at 7.7 - 7.8 (it's natural level?).
<This pH is far too low for a marine reef aquarium; you need to raise the alkalinity and the pH will go up. Do see elsewhere on WWM re: alkalinity, pH. If you haven't already read Bob's book 'Conscientious Aquarist', then please do buy or borrow this book.>
Our local aquarium supplier said that we could put in some starter fish to check that everything is ok and recommended Mollies which they supply as saltwater fish. The supplier also said we probably wont have to feed them as they will eat the plentiful supply of algae growing on the rocky reef wall.
<To some extent that's true, they do eat algae, but you should still be feeding them flake food as well once a day.>
We bought 8 Mollies in total (4 gold/ albino and 4 Dalmatian). A day later we were very surprised to find quite a few more! A browse through your extensive and very informative website further educated us on Mollies and their breeding habits. It turns out we have 3 Dalmatian males and the remaining 5 are females, of which at least one has obviously given birth.
Will the reef provide enough protection for the fry until they get larger?
<To a degree, yes. Once you start adding Damselfish, Hawkfish or whatever, most of these fry *will* be eaten.>
They disappear out of sight amongst the rocks and coral when the light is on and reappear like magic near the surface around the water heater when the lights go out. Also will they be happy enough dining on the algae like the adults?
<Yes, but you should be offering some flake food as well.>
Attached is a photo of the tank and a 2 day old Mollie fry (not the easiest fish to photograph!).
Out of curiosity, we told by a different source that another way to ensure new salt water fish don't contaminate your tank with viruses etc is to first bring the water in the bag you brought them home in to the same temperature as the tank. Then net and place the fish in fresh water that has been aged and is at the same temperature as the tank for 60 seconds, then transfer the fish via net immediately to the tank. Discard both the shop and fresh water.
This process of a fresh water dunk is supposed to kill off any salt water bugs on the fish (presumably as the bugs cant survive the fresh water dunking).
<Freshwater dips kill some, but not all, external parasites. They have no impact at all on internal infections such as viruses.>
Being completely new to the hobby and knowing no different, we followed this procedure with the Mollies and have not seen any problems yet but I am wondering how the fish survive this process unharmed. Is it like us holding our breath for a minute underwater?
<Sort of, yes. Freshwater fish can tolerate seawater dips, and seawater fish freshwater dips, for longer than the external parasites can tolerate them. So it's more like chemotherapy, the assumption being the dip will kill the disease-causing organism before it kills the fish. Much written on this topic at WWM. Do read here:
Do understand dips don't remove the need for quarantine tanks, and if you have a reef tank, quarantining fish is practically essential because you can't treat Marine Whitespot and other similar diseases without killing reef invertebrates.>
<Cheers, Neale.>

balloon molly birthing problems 5/3/10
We have a balloon molly that is probably about 6 weeks pregnant and she started going into labor today (5/2/10). She is very large and the fry are to big for her to push out do you have any tips on how to help her release the fry so that she doesn't die my wife has grown very fond of the two sisters that we got and would like not to lose either one of them <Balloon Mollies are inbred and extremely deformed, so they're more likely to have problems than other Mollies. Personally, I wish people wouldn't breed deformed animals precisely because of this, but I seem to be in the minority on this one. For what it's worth, healthy fish don't really go into labour as such. The females don't have pelvic bones around the birth canal in the same way as humans, so the babies should come through the vent very easily -- the pain humans experience during labour is nothing to do with birth as such, but because the pelvic bones have to open up somewhat and even then the birth canal is relatively narrow compared to the size of the baby. Most wild animals have quite easy labour, and it's only when humans have domesticated animals and bred them into new shapes that things
start getting complicated, e.g., with cows and sheep. Anyway, fascinating as this is, there's little/nothing you can do beyond ensuring good conditions for the Molly. Make sure she isn't stressed, e.g., by being
placed in a trap or net. Ideally, remove any males that would harass her.
Make sure water chemistry and quality is appropriate for Mollies, and that the tank is sufficiently warm. Include some floating Indian Fern for her to rest with. Just generally make her feel settled and comfortable, and then hope for the best.
Do female livebearers miscarry or die from not being able to give birth?
Yes and yes. Cheers, Neale.>

help!!! ACF... molly... Repro. Et? 2/26/10
I have been searching for the right answers to my questions and I am getting lots of different answers!!!
So I don't know what to do!!
<Like, totally!!!>
I have 2 African clawed frogs and 2 dwarf frogs!!
<Not in the same tank, I hope. They have very different temperature requirements, and the coldwater Xenopus (the big frogs) will eat the tropical Hymenochirus (the dwarf frogs).>
But, my one clawed frogs belly is getting bigger and bigger!!
<Oh noes!!!>
I am believing that she is going to be laying some eggs.
She's not as active as the rest of my frogs and she lays and kinda hides out like she is nesting.
<Not nesting. They don't sit in nests.>
But, the one other kind of frog always follows her around and gets on her and like hugs her here and there.
<It's called amplexus. Male frogs mount the backs of females, and use horny pads on their hands to hold on. As the females extrude their eggs, the males fertilise them.>
I dont know if there is anyway you can help me or not!
<She may not need helping.>
She was never this big and it just kinda came and I dont know what steps I should take!
<Do check you're keeping these animals correctly, here:
In particular, review aquarium size, water chemistry, temperature, and water quality.>
I also have 2 molly fish and they are 2 different kinds I know the one is a sunset molly and the other one is red with a black fin tail.
<Presumably in their own aquarium, and not with the frogs?>
Now, she has a big belly and it's pretty much the same story as the frog!!
<These are livebearing fish. Females will become quite big shortly before birth.>
She lays at the bottom of the fishtank and kinda goes into places and hides out. She never did this until I noticed her belly getting much larger! I dont know if they are or not????
<Mollies are finicky fish that need very specific things to do well. A large aquarium, lots of warmth, and hard, basic water, preferably slightly brackish. Do read here:
But, the things I have been reading says I need to separate them from the others so they dont get ate.
<"Don't get ate"? You mean "won't get eaten" presumably. Indeed, other fish may well eat newborn fry.>
But, here is another question can I put them both in a separate tank until they hatch or should I get 2 extra tanks for each one??
<Do read here, re: breeding:
I know they say about the nursery nets but if they both are going to have babies that is not going to work right???
<Putting the female in the net will stress her, and can lead to miscarriages. Best to let the baby fish hide among floating plants, and when you see them, move them into the breeding trap.>
I really hope that they are and I hope as well you can help me with this I am a first timer at this and am freaking out!!
<No way!!!>
Because I dont know what to do I want to learn about this as well as understand this!! I dont know if this matters or not?! But, I have 4 big goldfish,4 frogs, algae eater,2mollies,2tiger barbs I believe that is what they are called.
<Not all in the same tank, I hope. Unless it's a HUGE tank.>
So I really hope that you can assist me with this matter because I greatly appreciate your knowledge and helpfulness!!!!!!!! Thanks for taking your time to read this!!!
Sincerely, Maloree Peck
<Totally. Neale.>

Baby Dalmatian Mollies & Guppies -- 1/28/10
I am a new fish owner and I have a question regarding my baby Dalmatian mollies.
<Do start by reading here:
Mollies are easy to keep under some conditions, particularly in large tanks with clean, slightly brackish water. But they are VERY disease prone when exposed to less than perfect conditions. They are a bad choice for beginners.>
I have been trying to figure out their ailment but I get a myriad of possible diagnosis.
They were given to me since they were freshly born along with two baby guppies and I was happy but I don't have experience with owning fish. They have been doing good for 2 months and a half. During that time I have successfully changed the water in their tank etc.
<OK. Now, since Guppies and Mollies do well in slightly brackish water, the next step is a no-brainer. Add about 3-5 grammes of marine salt mix (not tonic salt, but the stuff used in marine tanks) per litre of water. This is very cheap to do, but will save you lots of heartache in the long term.
Next step is crank the heater up to about 28 C (82 F). While wild Mollies and Guppies are tolerant of cooler water, the store-bought fancy varieties (like Dalmatian mollies) are extremely sensitive to cooler conditions. Keep them warm!>
Recently, I have changed living locations within the past 2 weeks (high calcium water) and have changed their water with the faucet water treated w Chlor-out. My friend also gave me a new tank and gravel that have been used.
<How big is this tank? Newborn fish shouldn't be kept in anything less than 38 litres/10 US gallons. Sounds a lot, I know, but you need the water volume to minimise variations in quality and chemistry. In smaller tanks, most of your fry will be killed by poor water conditions. Trust me on this. Adult Guppies need at least 15 gallons, and adult Mollies at least 20 gallons for the smaller Shortfin Mollies, and 30 gallons for the Sailfin Mollies.>
I washed out the tank, rinsed some of the gravel. I put my fish in this past weekend and two of them immediately starting "itching'" and acting funny. Because of my inexperience, I wasn't too concerned... But apparently, it may be some type of parasite. A day or two went by, and one of them died. I inspected it looking for white spots, nothing. The fins did look shorter, and the mouth was sticking out.
<Likely Finrot. Review water quality, and act accordingly. Let's be clear here, virtually all "mystery deaths" are because the aquarist [a] didn't use a big enough tank; [b] didn't keep the water sufficiently well
filtered; and [c] didn't keep the fish sufficiently warm.>
Yesterday, I have noticed that another one is having trouble swimming, it looks bloated, has a bit of gunk in one eye, sometimes it swims really fast, a bit aggressive at times. As the day progressed it worsened. Its jaw was sticking out like the dead one, and because of this it has not been able to eat. It kept swimming in circles and even sinking head first or rolling over. I placed it in another bowl to observe it better with the same water taken from the tank to keep it from shock. It swam bumping into side of the container and was lethargic. This morning I found it dead.
I recently found out that the tank had fish that had died in it before! I dont know what were their symptoms but I know it was a big mistake not having cleaned the gravel. I feel so terrible!
<Learn from your mistakes. Read about Mollies, and set up a tank suited to them.>
I cant tell you much about water conditions, I dont have a filter yet, or a fish tank warmer so the water has been cold bc it we have been having 30 degree weather.
<Madness! These are tropical fish, and WILL NOT live in an unheated tank, any more than a Polar Bear would be happy in the Sahara. Get your act together!>
Until I get a tank warmer, I have sometimes used a Ziploc bag filled with warm water and placed it in the tank to warm up the water- My fish stay close to it. :)
<Smiley face or not, this is a pointless (and clearly ineffective) way of looking after your fish.>
My guppies are not showing any symptoms but I am afraid they may be next.
<I agree. All will soon be dead.>
How do I help my fish?
<Read. Make a list of what you need. Go shopping. Set up tank.>
<Cheers, Neale.>

My Balloon Molly, repro. -- 10/21/2009
I hope you guys can help me out. I have 6 balloon mollies (2 males and 4 females). And 2 of my females have already given birth without me being able to save any of the babies. Now one of my orange females looks completely different than the other two females did before giving birth.
She is (unlike the others) crookedly squared off in the front (the other two never squared off) and she has no gravid spot. But her butt is really swollen and looks like it could pop. And I think I can see baby eyes as
well. I put her inside my three-way breeder box already because I do not want to lose these babies as well. Am I doing the right thing?
<Mmm, is one approach... and if placed with sufficient space, time ahead of parturition, about the best one to assure saving the young>
And if so how much longer do I need to keep her in there? I.E. how much longer do I have until she gives us little babies?
<Perhaps hours to days... maybe a few weeks, to never if this fish is not really pregnant, capable of giving birth... Read here:
and the linked files above. Bob Fenner>
Adam U.

Will young fry eat newborns? 9/18/09
I purchased a Dalmatian Molly a week ago and found ten fry in the 55 gallon tank last night. This morning I placed them in a 3 part floating breeder minus the partition with a grate and placed my pregnant Creamsicle Molly above the grate. Is this advisable?
<No, not really. Much better to put the *fry* in the floating breed trap as/when you find them. The addition of floating plants to the main aquarium will help the newborn fry hide, and when you look at the plants through the day, you can scoop up and babies you find and pour them into the trap.
Dixie cups are ideal for this. The problem with traps is they stress the adult Mollies, raising the chances of miscarriages and other problems.>
Will the possible one week old baby fry eat the newborns whenever they arrive..
<No, the fry will ignore each other.>
no idea when she will pop?
<There's about 4-6 weeks between insemination and parturition.>
I don't know how big the fry are when they are born nor do I know how old they will be when the other molly will give birth. We have plenty of hiding places, holy rocks, plastic breeding grass, plants, etc. for the fry to survive, I believe.
<Livebearer fry live at the *top* of the tank, so plants and other stuff anywhere else is largely useless. Indian Fern is by far the best investment here!>
White sand covers the bottom of the tank and I think allows them to blend in more.
<Actually, freshwater fish can't stand white sand, and their colours will be better in tanks with darker sand or even plain gravel. Generally, avoid coloured gravel, sand, fake gemstones and the like.>
Thanks for your help.
<Cheers, Neale.>

Molly Babies 09/14/09
Hi, Great site by the way!
I have Dalmatian and Sailfin Mollies and around 3 weeks ago my Dalmatian molly gave birth so I caught the fry and put them in a breeding net and they appear to be all doing well. This morning I've got up to find my Sailfin molly has had fry too, which is fantastic as I wanted some young of both! I'm not sure where to put the new fry though! Should I put them in the breeding net with the other fry or will they eat them?
<These young are all about the same age; fine to mix together. Do feed often, small amounts...>
Appreciate your help on this
<Congrats! Bob Fenner>

Can a female Lyretail molly and a male Sailfin molly mate and breed? 8/26/2009
Thank you. Sarah
<Yes. Don't forget to keep twice as many female Mollies with your male Mollies, otherwise those poor girls are going to have an absolutely miserable life! Cheers, Neale.>

Breeding Molly 8/20/09
Dear WetWebMedia crew,
first of all I would like to thank for the help on aquarium topics in the past. Now I would like to have your opinion regarding my black mollies. I have 5 of them (1M+4F) in a 10 gallon heavily planted tank. Yesterday they produced 11 babies. Now please *tell me how to raise them up*.
<Hard to do in such a small volume... Ten gallons is difficult to keep stable, optimized, and mollies need space! To swim, grow, interact>
At present I separated them in a glass globe with little plant.
<If they are to be kept thus for a while, do get in the daily habit of changing out their water with that from the main tank...>
I offered them dried daphnia food but they refused. what can be their diet and should I put them back with the adults?
Thanking you
<Greenery of sorts... Please read here:
and the linked files above on Reproduction. Bob Fenner>

Selective Molly 8/13/2009
Hi, I currently have 4 female mollies (1 black, 1 silver, and 2 orange) and one Male black molly.(and numerous guppies, maybe 20). They are all getting along fine in my 55gallon tank.
<Very good. Since you have both Mollies and Guppies, consider adding some marine salt mix (as used in reef tanks, not freshwater/tonic salt) to the system, at about 5 grammes per litre (about 0.65 oz per US gal.). This will dramatically improve your odds of long term health.>
My problem is that my male molly seems to only pursue my black female.
<Sexual selection. It happens!>
Last week she developed some small white spots (Ich) so I quarantined her and treated her, she made a full recovery.
<The addition of marine salt mix, as mentioned above, will not only stabilise the pH and hardness, preventing the usual Finrot problems Mollies are prone to, it will also prevent and indeed cure Ick.>
But even as she was gone my male molly did not pursue any other females; and when I returned her to the community tank he immediately went after her and would not leave her alone. I'm worried that she may get sick again from all the stress put on her from our male. Is there anything we can do?
<Not really. Yes, persistent chasing by males will stress females, to the degree miscarriages become a problem. The addition of floating plants, such as Indian Fern (Ceratopteris) helps to provide hiding places and breaks up the line-of-sight, given the females some peace. Adding more females will also help, by spreading out the male's attentions.
And is there a reason my male molly would be selective to a molly the same color as himself, while ignoring the other females?
<Why do soccer stars only date lingerie models? What fish or folks see in the opposite sex will always be a mystery. Cheers, Neale.>

Molly Fry 8/8/09
About 3 months ago I purchased 1 gold molly, 1 black molly, and 2 gold dust mollies, I was told they were all female. Since then I have lost the gold molly and one of gold dust mollies gave birth to a batch of about 15 fry.
since the birth I have found out that the other gold dust molly is a male, and my female gold dust molly had died.
<Umm, why are these fish dying?>
My black molly has been hiding a lot and has started to look plumper, im assuming she's pregnant since the other female acted the same way (I know its the males batch of fry because they were virgin mollies when I
purchased them). my question is what would the name of the black molly and gold dust molly fry be?
<You'll have to see... the cross here may be from a species of "black molly" that will result in distinctive young, or a mix... Bob Fenner>
Jen O.

DALMATION MOLLIES, repro. mostly 8/5/09
I have a question regarding fan tail Dalmatian mollies.
I have three freshwater fish tanks. One is a 20 gallon, one a 29 gallon and the other is a 55 gallon.
<Mollies aren't really suitable for freshwater tanks. Do see here:
While they sometimes do fine in freshwater tanks, they often don't, so try and keep your options open with regard to tankmates and plants in case you need to add some marine salt mix.>
Not really knowing what I was in for, I purchased three fantail Dalmatian mollies. One day I noticed one of them being chased by another and decided to look up the difference between males and females.
<Males chase females, often aggressively. Keep at least two females per male.>
Much to my surprise, two of them were males and one was female. I also found out the female was very pregnant. I separated them with a divider screen and the female ended up having close to 45 babies. This was in March. The mother did not bother the babies at all. She never ate any of them or chased any of them. In the end due to some of them dying, I had about 40 babies.
In order to protect the babies, I moved the mother fish to a 10 gallon tank in April, and the two males to another tank. Then all of a sudden one of the males died. So far the other male is still going strong. Why this
fish died is still a mystery since it was very healthy looking.
<Mollies just don't do well in freshwater. They almost always do very well in slightly brackish water. There are endless arguments about why this is -- Mollies are predominantly freshwater fish in the wild -- but the reality is that in aquaria at least, adding 3-6 grammes of marine salt mix (not tonic salt!) per gallon makes a big difference.>
I read that females can have a batch of fry every 28 days or so even when no male is present.
<Not quite. Females can produce more than one batch of fry from a single mating, that is true. But eventually they run out of fertilised eggs, and will need to be inseminated once more if they are to breed again. For Mollies, you can expect 2-3 batches of fry per mating. The record is Heterandria formosa, a close relative of the Molly, which can have 6 broods from one mating!>
'We kept watching the momma and watching her and nothing happened. Then in May, we looked in the tank and there was another batch of fry. Again most of them survived. One of my questions is?? did moving her to another tank cause her to abort a batch of fry in April.
<Yes, stress can lead to miscarriages. This is one reason pregnant Mollies shouldn't be moved or, worse, confined to a breeding trap.>
Another question I have is we have mixed these two batches of fry together.
Some in the 20 gallon, 29 gallon and 55 gallon. We never separated the males from the females. We are so overloaded with fish that we are just letting nature take its course.
<What most folks do, eventually! Glassfish are good companions for Mollies in this regard, being accomplished predators while also doing well in slightly brackish water.>
We noticed that five of them started looking like they were pregnant.
Looking at the fins, we determined that these were females. Is pregnancy possible since they are not that old. The fish we thought were pregnant all of a sudden died. Could this have been from stress or were they too young?
<Mollies are sexually mature at about 2-3 months for males, 3 months upwards for females.>
My last question is in the 29 gallon tank, we have the Dalmatian mollies, three tiger barbs and one Plecostomus. All of the fish that died except one were in this tank. One of the fish that died was sucked up against the filter and the Plecostomus was actually eating it or sucking on it. I didn't realize that this fish would do that.
<Plecs are opportunists, and in the wild carrion certainly will be a significant part of their diet.>
In the 55 gallon we have two of these algae eaters and they never bother the mollies. Even though we are letting nature take its course, we are wondering why these fish died. They were doing great then they were dead.
Any suggestions???????
<See above.>
Thank you,
<Cheers, Neale.>

Breeding Mollies, 7/8/09
Hello, and thanks in advance for you knowledge and experience.
I recently started a nursery of Swordtail fry and have found raising the fry to be quite enjoyable.
I want to start another nursery and specifically breed a Sailfin molly with a Lyretail molly. I realize that it may take several broods to get the desired characteristics, but I wasn't sure that these two types of mollies would even breed due to the size difference.
<Will interbreed just fine, they are most likely either the same species or very closely related, or already hybrids. See here for more http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm .>
I have read hat the Sailfin mollies get quite a bit larger than regular mollies.
<They can get pretty good sized.>
Any feedback would be greatly appreciated.
<Have fun, but come up with a plan with what you are going to do with the fry now, it is not often easy to find homes for so many fish.>

Question: Mollies, Fry, and their communities -- 06/15/09
Hello, I would like to say that this website is fascinating and very helpful when it comes to our fishy friends and their care. I would love to thank those who maintain and run the site first and those who have
inquisitive minds asking the questions we should know.
<Thank you.>
Now here we go, since the pet stores tell you squat when you're purchasing fish and how to care for them, our tank has a motley crew of fish that seem to be getting along okay. The breakdown:
1 Creamsicle molly (currently in our 'sick bay' because shortly after purchase, she was showing some spots on her tail, so I'm treating her with Ich)
1 male black molly
2 female Dalmatian mollies
<Mollies do, almost always, do best in brackish water aquaria, with around 5-9 grammes of marine salt mix per litre. Marine salt mix -- not tonic/aquarium salt -- raises the carbonate hardness, increases general
hardness, raises the pH, and raises the salinity, a combination of factors that dramatically improves their overall health, especially if you live in a soft water area.>
1 unknown gender clown loach (I know they love schools, so we are looking to get 2 more and keep them in an isolation tank for a bit)
<These fish do get very large, and should be kept in groups bigger than 3. Intolerant of brackish water.>
1 Pecco- story on this guy, he's my husband's star fishy pupil. He's had it for 6 years and we got the bigger tank (45 gallon) for this big guy (11 inches) and plan on getting a bigger tank when we get a house and it gets bigger. Pleccy has sentimental value for him.
<Plecs, by which I assume you mean a Pterygoplichthys species catfish, will tolerate slightly brackish water, to around 5 grammes per litre, without problems.>
2 tetra ( ghost and Glo-light- were in a school at one point, but these guys are the only survivors from an Ich outbreak we had last year from the tetra school) and 2 male guppies.
<Tetras don't tolerate brackish water, but Guppies will, and in fact do very well in such conditions.>
First off- I know this is not the best combination of fish, but they seem to get along. Tips?
<Would divide the fish into brackish and non-brackish species, and house in their own aquaria accordingly. You can ignore this if you want, and if you have hard water and maintain good water conditions, you might be fine. But Mollies are notorious sensitive to water quality when kept under freshwater conditions, so if you find yourself losing Mollies, or having to deal with Finrot and/or Fungus, that's the reason.>
Secondly- we went out of town this weekend (the mollies are fairly new additions) and came back to inspect the tank. Well, much to our surprise we had fry. I threw a few extra plants in there for them to hide, but I was curious as to how often this will happen. After reading a bit on the Molly FAQ, the males seem to be amorous. Well, that's fine. But the question I have is- Will the Dalmatian females and the black male
I know they are the same species, but is it like dogs? Sorry to make that comparison, my parents were dog breeders. Will the black molly be lusting for my Dalmatians and Creamsicle? If so, will anything come from his wooing?
<Yes. Do remember to keep twice as many females as males, otherwise the males severely harass the females, to the degree the females are so stressed they miscarry.>
Not that I'd be one to complain if we had more fry, but I don't want some crazy over abundant molly invasion.
Thanks so much!
<Cheers, Neale.>

Mollies... repro. 06/02/09
I bought three fan tailed Dalmatian mollies.
<Oh dear... I say "oh dear" because Mollies are so much more difficult to keep than people imagine (or are led to believe). See here:
Two were males and one a female.
<Keep at least two females per male; otherwise the females will get severely stressed, basically harassed by the males who repeatedly have sex with the females, whether the females want to or not. It's really pretty
miserable for them.>
I had no idea what I was in for.
<It's often best to just buy females.>
Well of course the female got pregnant and I separated her from the males by using a net divider.
<Females Mollies can't be kept in traps/nets; they're too big. It stresses them, and often they miscarry, even assuming they don't jump out.>
She ended up having about 40 babies.
I kept the mother fish in with the babies and all survived. Of course I found out that the female can hold sperm and continue to have babies up to 6 months.
<I don't believe this is actually true. Poeciliids can stall the development of some of the embryos produced at each mating, so they're "storing" embryos rather than sperm. The six-month record applies to a fish called
Heterandria formosa, a tiny little fish sometimes called the Least Killifish. Moreover, Heterandria formosa can vary the rates at which embryos so precisely that the female drops a few fry ever few days, as opposed to the 45 days that occurs between each brood produced by things like Platies. So far as I know, this process of delaying embryos, known as superfetation, has not been reported from either Poecilia (Lebistes) or Poecilia (Mollienesia), i.e., Guppies or Mollies. What is true is that Mollies "ovulate" for want of a better term as soon as eight days after giving birth, meaning they can produce a new brood of offspring very
I ended up moving the mother to a ten gallon tank by herself. She looked like she was pregnant but never produced any babies. Did my moving her cause her to abort?
<Can do.>
Then about 28 days later, I noticed she had another batch of babies. This time it was around 30. All survived. Again, she got very huge and was due around May 18th, 2009. I had moved her back to the 20 gallon tank with her babies but no babies and she doesn't look fat anymore. Did she again abort or could 1 month old babies eat the fry.
<Yes, fry can be cannibalistic, though adults tend to be too.>
I need to know what to do.
<Apropos to what? Do you wish to rear the fry? If that was the case, I'd keep the adult Mollies in a big aquarium with lots of floating plants. I use Amazon Frogbit and Indian Fern in my tanks. Stems of tall plants such as Hygrophila are good, too. Ideally, maintain slightly brackish (SG 1.002-1.003) but at the least, hard and alkaline. Every day, you can scan the plants for fry, and remove them to the 10 gallon tank, and rear them there. Again, stock that with plants, and ideally put it somewhere green algae will grow. I have my fry rearing tank (mostly Limia but also Corydoras and Halfbeaks) on a sunny, but not too hot, windowsill, so the plants and algae grow rapidly even though the tank has no hood or lights.
The fry of different ages largely ignore each other because they have all the algae they want. I also rear snails and shrimps in there, so it's a fun tank.>
I have a 55 gallon tank that has 3 Bala sharks that are about 9 to 10 inches long. Is it wise to put the first batch of babies in that tank with the sharks or will they become food. I have a 10 gallon, 20 gallon, 29 gallon and a 55 gallon tank.
Thank you,
Overdosed with Babies in Nevada
<Cheers, Neale.>

molly genetics 06/02/09
I have kept mollies successfully for some time now and I would like to breed a silver lyre-tail strain.
<Surely already exists?>
My questions are, what colour genes are dominant in mollies, is the pot-belly/balloon gene dominant and is the lyre-tail gene dominant or recessive?
<Sorry, not a clue! Your best bet would be to contact one of the many Livebearer Associations around the world. There's a (very) old book called "Genetics for Aquarists" that largely covers Guppies, and while Mollies are a different Poecilia species, I'd expect you'd be able to learn enough from that book to get your experiments started. I would warn you that simple dominance as you learned in high school is rarely what actually controls phenotypic characteristics in reality. Human eye colour for example is controlled by a number of different genes, and consequently rather difficult to predict.>
Thanks in advance, Emma
<Cheers, Neale.>

Nursery Filtration Question 5/13/09
Hello Crew,
*Disclaimer* ---> I'm new to both the hobby as well as to WWM
Here is my situation. I've managed to get my main tank cycled up and running with no problems. I've added my livestock and they seem happy and content. Content enough to have one of my mollies pop out a couple dozen fry. I've started and cycled a 5 gallon nursery tank so I could get the fry out of the net breeder I was using as a quick fix. The issue I'm having has to do with filtration for the 5 gallon. I moved the fry over and got everything going, including the Whisper 10i that came with the tank. When that bad boy cranked up the current was so strong the fry could do nothing to overcome it. I traded down to a Whisper 3i and had the same problem (filter inhaled 2 in the 20 min I left it on). I've also tried a TOM Aquarium Products Mini Internal Filter Model 1250 (adjustable flow immersible 3-stage filter) with same results minus the fish loss. Is
there anything I can do short of just water changes to filter the 5 gallon?
<Yes... I strongly suggest you look to/use a sponge type filter... a good air-lift type will do splendidly here... My fave is the Hydro-Sponge line>
<Welcome. Bob Fenner>

Baby Mollies: It's what's for dinner: FW Stocking 4/1/2009
OK I have a 25 gallon take and I have:
2 mollies,
3 Glo fish,
3 neon tetras,
2 angel fish,
1 gold fish,
<Inappropriate for a tank of this size and with these tankmates.>
2 snails and
1 Pleco:
<Inappropriate for a tank of this size, can grow to over 18">
The black molly when I got it looked like she had swallowed a marble. she was really round, so I didn't know if it was pregnant or if it was a pop bellied molly.
<Likely pregnant>
But I was looking the other day and she is not round anymore so I am assuming it had babies, right?
<A safe assumption, yes.>
but I haven't been able to find any in my tank. so did the others eat them or did the molly even have babies to begin with?
<Likely they were eaten.>
<Please read here, as well as the linked pages at the top:
http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm >
thank you,
<You're Welcome>

Pregnant mollies 3/21/08
I have two pregnant mollies who have been trying to give birth since last night. They both have a fry sticking out of them that are stuck. What do we do to help save the mollies?
<Distressing as this to see, there really isn't much you can do to help beyond ensuring your Mollies are maintained in optimal conditions (clean, warm, slightly brackish water). If the babies can come out, they will; if there's no movement in, say, another 12 hours, then you'll probably need to pull the babies out manually using forceps. This will almost certainly kill the babies, but chances are they'd be dead by then anyhow. Good luck,

Pregnant balloon molly gestation-- 02/28/09 I am puzzled about a female balloon molly that I purchased. I got this fish on 12/16/08. At the time the fish appeared pregnant. <Not sure you can tell with Balloon Mollies. They are, by definition, swollen.> As of today, the fish is still pregnant and getting bigger everyday. <Are you overfeeding here? Are you maintaining her in freshwater rather than brackish water conditions? Mollies are herbivores and prone to constipation and other problems if given regular fish food. Dried foods cause particular problems. They don't do well in freshwater, and are much healthier in slightly brackish conditions, around 6 grammes of marine salt mix per litre of water being ideal. Obviously most freshwater fish can't tolerate salt, which is why you shouldn't keep Mollies with anything other than salt-tolerant species.> Here lately her appetite has somewhat decreased. I know how a fish appears that has dropsy. The scales are not protruding and the fish swims in a horizontal fashion. Can gestation last 73+ days?? <No.> I promise this fish was pregnant when I purchased it. <With respect, I'm not sure you promise anything of the kind! If the Molly is swollen, I'd perhaps consider the factors mentioned above, and act accordingly. Do see here: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm Cheers, Neale.>

New to mollies, new fry and questions 2/20/09 Hello! Very informative site. Glad to find knowledgeable and enthusiastic folks willing to share time and info about our fishie friends. My question(s): Have two female mollies (one about 3 yrs old, the other adopted over Christmas) and this weekend introduced a male. Just THREE days later, one of the females gave birth to only three fry, though she still seems VERY pregnant. I separated the male (as he is rather relentless in his pursuit of the pregnant molly) into a floating plastic breeder type enclosure (only thing I had on hand) and also cordoned the fry in a breeding net. All fish are still in same tank, within their respective enclosures. My first question is whether it is possible that my pregnant molly got stressed by a recent move (hours before the birth. I moved the entire tank to another side of my room, CAREFULLY), or is it possible that the aggressive male caused her to birth the fry? Next, I just read something about fry needing a different nitrate level than adults, and I am worried that maybe I should not keep the fry in the community tank--though they seem to be doing great (save for one who got stuck between the net and the plastic frame of the breeding net and died ; ( )? I also get algae in my tank; I have one algae eater and I do scrub the sides often enough to maintain crystal clear water (I do leave a little bit for my algae eater though), and I read that too much algae is also not good for fry. Finally, my male is NOT happy being so constricted, but every time I let him out he pesters the pregnant molly incessantly! (I mean INCESSANTLY!) The older molly also picks on her a bit too. : ( I was considering getting another female or two...what do you think about that. Aside from the three mollies and one algae eater, I have 5 neon tetras (who stay together and never bother anyone), so I am pretty positive I have ample room for additional fish. I have a bio-wheel filter (with two wheels and two filters), an aquarium heater (which I keep around 78-79 since the fry were born), and I also have two aeration hoses, one on either side of the tank. I only have two very small live plants, and after reading a lot of molly info, it seems that I may need to add more. This is a long email, but yours is the best Q & A site I have found, so I really appreciate your taking the time to read through this and look forward to your advice/answers! Peace, Jenn <Hello Jenn. Yes, female Mollies (and livebearers generally) are stressed when moved. At the most extreme, they can miscarry. Mollies are far too large for breeding traps and should never, ever be put in one. Frankly, only Guppies are small enough for them, and I wish they were sold with a warning label on the box! Secondly, aggression from males can, will stress the females. As I've written repeatedly, males should be outnumbered by at least twice as many females. Keeping equal numbers of males and females is cruel, precisely because the males don't treat the females well, and will essentially forcibly mate with them again and again, even if the female is already pregnant. In the wild this instinct is understandable, the males being smaller and much more likely to be eaten to predators. Males also hold territories containing schools of females, and spend much of the time driving off other males. So the actual opportunities to mate are few, and need to be seized. But in the aquarium the females can't hide, the males don't have any challenges, and the result can be the female fish equivalent of Hell. Personally, unless the tank is above 180 litres/47 US gallons in size, your tank should have just a single male from a large Molly species (e.g., a Sailfin Molly) or up to three specimens of a small Molly species (e.g., a Black Molly). All the other Mollies should be females. Your tank should also have lots of floating plants. These are crucial for two things. Firstly, they provide hiding places for the fry, making traps and breeding nets irrelevant. Secondly, they provide cover for the females, so they can rest hidden away from the males. All Molly species need minimal nitrate levels when maintain in freshwater aquaria. As you have hopefully read before, Mollies do not always do well in freshwater tanks, and sodium chloride helps to reduce the toxicity of nitrate, helping the Mollies do better. Mollies do even better in brackish water tanks where marine salt mix is used, because this raises the carbonate hardness and pH, further improving their health. Obviously, Neons can't be kept in tanks with salt or marine salt mix added, which is why Mollies and Neons are NOT COMPATIBLE fish. Algae is the perfect food for adult and baby Mollies alike. Much of this written elsewhere on this site; start at the link below, and follow the links: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm Cheers, Neale.>

Fry and Water Changes 2/12/09 About five days ago I picked out a female Molly and about three hours later she had 22 babies. I have had molly fry before and I have all the food and extra tanks needed to raise them. <Cool.> There is no gravel in the tank (because of past babies dying from digging themselves under it and dying) so I can see all the leftover of the liquid food. <This isn't how they died. The fry can't dig into gravel. Usually what happens is gravel traps food and faeces, and as this organic material decays, it removes oxygen and favours the growth of fungi and bacteria. It's these things that can (and often do) kill fry. So as you've observed, it's often best to rear fry in tanks with no gravel, and that's what many serious breeders do.> I want to vacuum that out the particles but I don't want to suck the babies up. <You'll find a turkey baster very useful for this.> If I remove the babies to vacuum around half to 3/4 of the water would they suffer from too much stress? <Nope. The main thing is you don't suck the babies up!> Or is it just best to try to net out the "floaties" as much as I can out? <The cleaner the tank, the better.> Thanks! <Cheers, Neale.>

Re: Fry and Water Changes (Mollienesia; maintenance) 2/15/09 Wow that turkey baster works really well! I am currently sucking up all the waste left over at the bottom daily and the nitrate, nitrite, pH, and alkalinity are all picture perfect for this small nursery! Thanks so much for the advice, Hannah (I now keep the turkey baster in my "big bucket of fish supplies") <Glad things are working out. Sometimes the best solutions are the simplest! Cheers, Neale.>

Mollies Breeding With Guppies? ~ 01/09/09 Hi, I have a 12 gallon tank with 3 Mollies, (one female and two males I know its not recommended-just my luck) and 3 male Fancy Guppies. My female Molly has had many babies before with the other Molly males. (I have watched them mate) I recently looked into the tank and one of the fancy guppies was mating with my female Molly. (for a couple hours) I am 100% sure it was that because of past experiences. So I have some questions: 1) Can Mollies and Guppies successfully mate? (like successfully fertilize?) <Mmm, no, not as far as I'm aware... there are members of the family (Poeciliidae) that can produce via young from crosses... e.g. guppies and platies, but Mollies (now Poecilia spp., formerly Mollienesia) do not cross successfully with guppies (Poecilia reticulata), though they can interbreed amongst Molly species> 2) Can the Molly give birth to hybrid babies? <Not from crossing with a guppy> 3) And if so, can the babies survive? They wont have deformities? 4) If so, with they have traits of both parents? (Female Molly is a Dalmatian Molly and the Male yellow fancy guppy. he is just white and yellow) 5) Is this common? Do you know of any surviving hybrid Molly/Guppies? <The behavior of reproduction is common amongst the common Poeciliid livebearer species, but ... the young produced from species crosses tend to be more feeble, not survive for long> Thanks so much! <Do please write back if you "hear" otherwise. Bob Fenner>

Re: Mollies Breeding With Guppies? 1/11/09 Will do. I'll tell you if anything happens... Thank you Hannah. BobF.

Molly pregnancy 10/29/08 Hi, I've recently bought a new 29 gal aquarium, this is the first aquarium I've ever owned. I bought 2 Dalmatian mollies (1male, 1 female) and a silver fin molly (female). 1 week later I bought 5 tiger barbs and 1 green spotted puffer. <The Tiger Barb is out of place here: both the Mollies and ESPECIALLY the Green Spotted Puffer will need brackish water, with at least 6-9 grams of marine salt mix (Instant Ocean type stuff) every liter. Kept in freshwater conditions, Mollies are sickly and disease-prone, and Green Spotted Puffers simply die prematurely.> My silver fin molly had a hunched back a few days ago, now it does not but it's stomach has gotten considerably larger. I have a few questions: 1. How long is a molly pregnancy length? <Between 1-2 months, depending.> 2.What is the hunched back that the molly had, a disease? <Deformities are common in Mollies, particularly the inbred fancy forms. But maintenance in poor water conditions, e.g., freshwater conditions, can lead to things like the Shimmies.> 3. How many babies do mollies usually have? <Very variable, but expect a couple of dozen at least.> 4.How can I tell if my silver fin molly is pregnant. <If it's been with a male, then it's pregnant. They're pretty promiscuous!> 5. My silver fin molly goes down to the bottom of the tank and lays there and breathes away from the other fish, and refuses to eat, is this pregnancy or death? <Death isn't far, to be sure. Almost certainly caused by poor water quality (detectable nitrite or ammonia) and/or the wrong water conditions (must be hard, basic, and with some marine salt mix added). The use of marine salt mix rather than "aquarium salt" is the thing -- marine salt mix contains salt plus various minerals that raise the hardness and pH.> Please respond. -Zack <Much about Mollies here; start with this piece: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm Mollies are great fish, but not "easy" when kept in freshwater conditions. Cheers, Neale.>

Re: Molly pregnancy (environment, health) 10/29/08 Thanks for the info! But to comment on what is happening with my mollies, my 2 Dalmatian mollies (1 female and 1 male) seem to be doing fine, the male is showing allot of interest in the female Dalmatian. Is it possible that they will be fine in the freshwater conditions? <Almost certainly not in the long term. Just look over the letters we get from Molly keepers here at WWM. Mollies may be freshwater fish in the wild, but they just DO NOT do well in the average freshwater aquarium. Very expert fishkeepers understand their sensitivity to variations in pH and nitrate/nitrite concentration. But the casual aquarist can't manage these issues correctly, and the Mollies get sick. Adding marine salt mix is cheap, easy, and benefits all Mollies as well as most livebearers -- so it's a no-brainer.> My tiger barbs also seem to be doing fine, so will the mollies just die prematurely? <Probably, yes. Tiger Barbs are fin-nippers as you may or may not know, and I do not recommend them for community tanks.> When I bought the green spotted puffer they sold it in the freshwater area and said it would be fine, with the green spotted puffer by how long will his life be shortened? <"How much his life is shortened" is neither here nor there, since we're talking about animal welfare. But on the average when these fish are kept in freshwater conditions they rarely get to 50% their lifespan in brackish water conditions. Mortality rates from issues such as Fungus are MUCH HIGHER. There is ABSOLUTELY no excuse to keeping this species in anything other than a brackish water tank. For a start, it's NOT a community fish and WILL NEED to be kept alone eventually -- wild Puffers of this species bite the fins of other fish for food, and will view Mollies as a swimming buffet. So it will have its own tank. If it is in its own tank, what excuse is there for not adding some marine salt mix? At 6-9 g/l you aren't going to break the bank. A big old box of Instant Ocean will last a very long time at this dosage, and set against the cost of medications and replacing dead fish, it's a no-brainer as well.> We live in an area with naturally very hard water and what I do to the water be fore I put it in the tank is add water conditioner and stress coat and stress enzyme, and aquarium salt, is this fine do to the water? <Add marine salt mix, not "aquarium salt". The hardness of your water is a good thing, but it isn't an excuse. Even 5-6 g/l will make all the difference to your success with Mollies, and will be good for the Puffer while he's in there. The barbs will need another tank, needless to say. Do PLEASE research your fish before buying them. When you walk into a pet shop, the selection of fish is like the selection of mammals in the zoo. No-one would imagine polar bears, monkeys, camels, mountain lions and mice would all get along -- yet people assume so with the fish on sale. Each has specific needs re: temperature, water chemistry, aquarium size, diet, social behaviour, etc. Books help here, and if all else fails you can write us as say "I saw this great fish at the fish shop... Will it mix with what I already have? Does it need any specific water or aquarium conditions?" We'll write back and let you know. In the case of the Pufferfish and the Mollies, I literally wrote the book on them for TFH ('Brackish-Water Fishes', feel free to grab a copy) so I know of what I speak.> How often do mollies become pregnant? <All the time, pretty much.> And when you say if she has been with a male? She's in the same tank but he hasn't shown much interest in her. <Sure he has. You just haven't seen him mate with her. The males instinctively mate with anything, even different (though related) species.> Thanks for the info. -Zack <Cheers, Neale.>

Male Dalmatian Mollie - Pregnant?!?! 8/5/08 Hello, I will start by saying thank you for all of the help that your website has provided for me, and my fish. <Thanks for the kind words.> I am a bit confused by one of my mollies. I have two tanks of Dalmatian mollies - one 20 gallon for my females - 2 adults, 2 adolescents, and my Dalmatian plantation of about 12 babies (for now); and one 14 gallon that I set up in June to move my 4 male mollies into. I only bought three female mollies for my first (and, at the time, only) tank - and have been blessed with so many more ;-) <Hmm... 20 gallons is a bit small for Mollies, and you're going to find aggression between the males and the males chasing the females a real problem. I recommend Mollies kept in nothing smaller than a 30 gallon tank.> My question is about one of the male mollies, Pat. I have been thinking about taking the males in to the LFS because I just don't think they are happy - first because they are in a 14 gallon tank (they are still small, only about 1" long), and second because there are only males in the tank - and what fun is that. <Would tend to agree! I like mixing male and female livebearers. Watching their social behaviour is fun. But the secret is to provide the fish with ample space and lots of floating plants for hiding places. Keep two (at least) females per male. Done like this, the males don't get too annoying, and you'll have plenty of young fish to take to the pet store for credit. If you don't want to keep the babies, then just add a predator. Given Mollies do best in brackish water and shouldn't be kept in a freshwater tank, Knight Gobies (Stigmatogobius sadanundio) are ideal for this, and will thrive at the SG 1.002-1.005 you should be keeping your Mollies at. Knights will eat any fish that fits in their mouth! Crazyfish (Butis butis) would be just as good and need the same salty condition.> Anyway, they are always, always pestering each other - poking under each others bellies, etc. Two days ago, I noticed that one of the males started hiding, hanging in his cave or at the top of the tank. The other three fish have pretty much left him alone since he started acting like this. He's starting to look like a balloon molly - his belly is very round (much like my females look before they give birth - doesn't resemble bloat). He's breathing very heavily, mouth open constantly - just looks very uncomfortable. Today he had this long stringy, poop-like thing hanging out of him - it was opaque/white with a few solid white looking "pebbles" throughout the string. It has since broken off, now there is just another, shorter, string hanging there. Nothing else that I can see going on with him. <Absolutely normal, I'm afraid.> About the tank... 14 gallons, brackish water (S.G. 1.012), ph 7.4, Ammonia, Nitrites, and Nitrates all zero, Temp - 80 F. This tank has been set up since June - for these male mollies (who were born in January). p.s. The water still appears cloudy - but the numbers all look good. Also, I did a 20% water change today. <Sounds fine, though honestly a bit small, and the cloudiness will be related to inadequate mechanical filtration in all likelihood. Could simply be overstocked. You don't need this much salt for Mollies to do well, though needless to say they'll thrive in it. My take on salinity is this: a lower salinity, but more water changes, will cost the same but do your fish more good by keeping nitrates low.> So, what do you think could be wrong with Pat? I am 99.99% sure that he is a male - same anal fin as the others, but I keeping thinking that all signs point to pregnancy, if only he were a she. I just don't know if I should wait this out, or try something else for him - please advise. <Sounds ill rather than pregnant. The symptoms are non-specific, but I'd perhaps treat with an antibiotic like Maracyn and an anti-Helminth like Prazi Pro. If these don't help, get back in touch.> One other quick question - I have read differing info on what size tank mollies should be in (some say 10+, others say 30+) - do you think that the 14 and the 20 gallon tanks are too small? <Yes.> Thank you, again, for all of your help - past, present, and future. Amy <Cheers, Neale.>

Molly eggs 08/02/08 Hi Crew, I've been reading your forum for a few months now, whenever I have questions about my pond or aquarium, and your site has helped immensely! Thanks for a job well done! <You're welcome, and thanks for the kind words.> I was searching for information about mollies and egg laying. I know they are livebearers, but just today, I witnessed my silver molly lay 2 eggs! <You really didn't. What you might have seen was most likely miscarriages. Mollies are easily stressed, e.g., by breeding traps or pestering males, and the result is miscarriage of the embryos.> I'm assuming these are underdeveloped embryos, as I also witnessed one fry come out with what seemed to be an egg attached to its belly. I think that one didn't make it. Anyway, she gave birth to some healthy fry too. I was just curious about the eggs that came out. <Does happen from time to time with most livebearers if exposed to conditions not 100% suitable to the species in some way. Review tank size, whether there are males in the tank, water chemistry/quality.> I tried searching online, but would only get links such as, "mollies do not lay eggs, they are livebearers." Thanks for any information you can share! Kristine <Cheers, Neale.>

Molly question, behavior 7/1/08 I have a female Lyretail mostly black, (not enough white to be Marble or Dalmatian), molly, that is constantly being pestered by a male Lyretail Creamsicle molly. I've seen them mate at least 100 times. Will he ever stop pestering her? <Not likely.> Assuming she is with fry, when should I expect her to give birth? <About every 6 weeks or so depending on conditions.> Is there any way to tell when she is ready? <Easiest way it that she will be especially round, also sometimes a gravid spot can be seen. See here for more http://www.wetwebmedia.com/fwsubwebindex/livebrrreprofaqs.htm .> What color do you think they will be? <Impossible to tell, could be almost anything.> I heard that black mollies only give birth to black female mollies no matter what color the mate is, but I find this questionable? <This is not my experience.> Thanks, Laura <Welcome> <Chris>

Breeding, Mollies 6/19/08 I have a quick question for you guys tonight. I have 7 adult mollies, 2 bring males, anyway I have a large amount of fry on my hands, 35 to be exact. I want these guys to live a full and prosperous life. Unfortunately I only have a 20 gallon and a 10 gallon tank that cannot house all of these fish. Do you know of a place where I can pass these babies on? I live in the South Bay area near San Pedro, California. Thank you!! Alia <Contact your local fish stores, post what you have on Craig's List... likely some local folks can make good use of your excess. Bob Fenner>

Cloned fish... Molly repro. f' 4/24/08 http://news.bbc.co.uk/2/hi/uk_news/scotland/edinburgh_and_east/7360770.stm <Neat... yeah, "Amazon" Mollies. B>

Dead Molly Baby 4/20/08 Hi everyone. I love your site and find it very helpful. I am hoping you can answer a molly question for me. My mama molly had a baby (just one) on Wednesday. First of all, I thought she would have a whole bunch because she was really big. I had put her in a breeder net about a week ago and I made sure I had plenty of fake plants in the net for the babies to hide in. Well, Friday the baby was dead. I found it at the bottom of the net on the gravel. What do you think could have happened? I have a total of 4 mollies and 2 goldfish in the 10 gal tank. I am getting rid of the goldfish because I have learned they need different water conditions than mollies, and they are too big for a 10 gallon. All my fish seem fine. I think I have another pregnant molly, but not too sure yet. Should I put her in the net when she gets closer to having the babies or should I leave her free in the tank? I want to raise mollies really bad. I think they are really pretty and fun fish to watch. Any suggestions besides getting rid of the goldfish? Thanks for your help! Shona <Hello Shona. You say your fish "seem fine" and yet you have dead baby fish. So things obviously *are not* fine. Let's take things from the top. 10 gallons is too small for either Goldfish or Mollies, let alone both. You will find it extremely difficult, if not impossible, to maintain good water quality. This isn't a topic up for debate, and when we say this here at WWM, it's on the basis of decades of experience. Mollies need at least 20 gallons, and Goldfish honestly need 30 gallons upwards. So yes, they need new tanks. Next up, Mollies are an order of magnitude hardier when maintained in brackish water. Again, there's no point debating this, because it's a statement of fact you ignore at your peril. Thirdly, Mollies must never be put in breeding traps. Mollies are too big and easily stressed. Among other things they miscarry, and that's likely what happened here. Breeding traps have almost no useful function in fishkeeping, and are mostly a way of allowing shops to get lots of money from inexperienced fishkeepers in return for cheap bits of plastic. If you want to raise Mollies, here what you do: transfer the females to a 20 gallon aquarium filled with brackish water and with a high level of carbonate hardness (using 3-6 grammes of marine salt mix per litre should take care of both salinity and hardness; don't waste your money on "tonic salt" or "aquarium salt"). Add lots of floating plants. Every day, check the plants for baby fish, and remove them to the 10 gallon tank, filled with water of identical water chemistry. There's a reason fish farms rear Mollies in brackish water: it works! Your Goldfish should of course be kept in a 30 gallon tank with regular (not brackish) water, or better yet a pond. This is what you need to do for successful fishkeeping. Your move. Cheers, Neale.>

Re: Dead Molly Baby 4/20/08 Thanks for the advice. As soon as I find a new home for the goldfish they are gone. I'll not use the breeder net again! Do you think that is what killed the baby? <Difficult to say precisely, but certainly one of the more probable factors. When you find dead baby fish immediately after birth, they've either been snapped at by the mother, or simply miscarried. In either case, a breeding trap is a probable cause.> Any particular kind of floating plants that you would recommend. I have lots of plants (fake) on the bottom, but no floaters. <Hornwort and plain vanilla pondweed ("Elodea") do just fine. Neither costs much, and they can be replaced cheaply and easily if they start looking a bit sad. Plastic plants left floating at the top will work just as well.> I'm looking for a bigger tank for my mollies. Thanks for the help! <You're welcome. Cheers, Neale.>

Determining sex of molly fry 4/15/08 Hello! <Hi> I bought two Dalmatian mollies about four months ago. I asked the pet store worker for males because I didn't want fish babies due to a fear of running out of space in case of population explosion. Despite his assistance that he could tell the sex, I fear he was either wrong or my "male" mollies had babies. <Can change sexes when necessary.> I had originally had two Dalmatian mollies and one silver one but, after some research, found the silver one to be a male and gave him away. The first batch of fry the female(s?) had all died. They stayed very tiny, lived for about a week or so and then just suddenly died. That was in January. In the beginning of February I woke up to discover about 16 baby fry in the tank. Shortly after (maybe a few weeks) both female mollies died. I think it was dropsy and I tried to treat the tank but unfortunately they just didn't make it. The baby fry share the tank with a Gourami, at this point, and one lonely sunburst platy. The Gourami sort of chases them but they've gotten rather large, probably tripled in length, and they're swift enough to stay away. I did have four that 'disappeared' and I assume they weren't quite quick enough. My question is at what point will the baby fry start breeding with each other? <Most sexually mature around 6 months, some longer.> I want to separate the males and females so I don't get any other babies because I have no way to keep them all safe and healthy if they breed indefinitely. <It is almost impossible to due, late blooming males which look like females initially, sex changes, they are quite adapt at procreating.> I keep checking them, as best I can, but they all look the same to me. <They will for the first 6 months generally.> They can't all be female can they? <Nope, just not showing yet.><<Mmm, actually... can/could be all of one sex... even just temp. can vastly alter sex ratios of young. RMF>> This has turned into a small mess for me and I'm trying to mitigate damage. Thanks in advance, Mary <Best bet is to figure out a way to get rid of the fry humanely, be it larger, faster fish, a pet shop willing to take them, or some other means.> <Chris>

Strange oozing in very pregnant Molly 4/6/08 Let me start by saying I read through your FAQ on Molly reproduction (I have the whole thing printed out and have referred to it several times since finding out I have a very pregnant molly), and tried to use the search tool. That didn't work, and please accept my apologies for this email if it turns out that this is posted already. Either my computer sabotaged me, or I couldn't figure out the search tool. I tried it several times and all I got for my efforts was a blank page. Anyway, here is the scenario. We have a 60 gallon long tank that has been running now for about 2 and a half months. We use a power filter (Aqua Clear 110), as well as an undergravel filter, and we have ammonia and PH monitors in the tank. Since we live in the desert and our water is very hard, we bought a tap water filtration system which we use for our bigger water changes. <Don't waste your time softening the water for Mollies; liquid rock is what they like! You want hardness 20 degrees dH or more, and pH around 8. Ideally with marine salt mix added for all kinds of reasons. Your should never, ever use water from a domestic water softener in an aquarium. It has all the wrong mineral composition for fish.> We do about a 10% water change weekly. <Not enough really; Mollies are super-sensitive to Nitrate, and in fact pollutants generally, and they need at least 25% weekly water changes, and quite likely more if you aren't using salt (salt moderates to toxicity of nitrate).> Just recently, when a fish died within days of being introduced, we took the fish back to the store with a water sample, which they said was the best water quality they had ever seen in the area. This might be a little more history than you wanted, but just in case any of it is relevant, here it goes. <OK.> For starter fish we picked out 6 silver Lyretail mollies and 6 Danios. The very next day one of the mollies was dead (seemed to be fine the night before) and soon after a molly we believed to be extremely pregnant turned out to be a case of dropsy and though we moved her to a hospital tank and tried to treat it, being unsure what to do and hesitant, we failed miserably. <Mollies are in fact terrible fish for "starting" a tank, because they are incredibly sensitive to variations in water quality and chemistry. Mollies aren't community fish and they aren't fish for beginners; they're lovely fish best kept in very specific conditions all their own. In freshwater tanks something like 50% of them either get sick or simply die within months as far as I can judge. In brackish water and marine aquaria they are virtually indestructible. That tells you everything you need to know about them, really!> That left us with two males and two females, so we gave away a male to improve the ratio. The tank and the mollies all stabilized, and we had no problems until about 4 weeks ago, when the smaller female seemed to have some kind of fungus. We treated it, to all appearances successfully, but soon after being returned to the main tank she unexpectedly died. We did about a 20% water change. None of the Danios had any problems. <This is all absolutely standard when Mollies are kept in freshwater tanks, especially if you're "softening" the water using a domestic water softener. I can't make this clearer: Mollies need hard, basic water, preferably with salt added. They aren't freshwater community tank fish.> By now (4 weeks ago), the surviving female is extremely huge, overnight the ammonia levels are down to almost nil and practically the next day the female drops about 18 babies (they are very good at hiding so this could be an inaccurate count). We didn't have a nursery tank, but we sectioned off part of the main tank, provided floating fake plants for cover and plenty of baby food. About two weeks ago, we added 4 small catfish, 4 algae eaters (that's what the store called them, I can't be any more specific than that for the moment), and 2 rainbow sharks, with the babies still in their separate section. <I hope your "algae eaters" aren't Gyrinocheilus aymonieri or Pterygoplichthys multiradiatus. Too big, too difficult to keep, and in the former case, aggressive towards tankmates once adult.> All fish seem to be getting along fine, and all seem to be in good condition. The babies seemed big enough to join the rest of the fish last weekend, and we removed the partition. We're hoping there are still 18 of them, but we have yet to see more than half a dozen at a time since. Now, the question... Over the last few days, on about 3 different occasions I noticed that the (still) very pregnant Molly seemed to be oozing something. whatever it is is perfectly clear, and can be detected only by the tiny air bubbles that get trapped in it. It is stringy and long, appears to be coming from the belly area, and judging from the pattern of bubbles looks very slimy in nature. The Molly is acting perfectly normal, eating and swimming as usual. The male, which had been busy getting acquainted with the new fish in the tank for the last two weeks, is back to chasing her around, and she is taking t with her usual patience. We tested the water and all is fine, the PH and ammonia monitors register safe levels and none of the other fish are showing any signs of this thing, whatever it is. The Molly doesn't have this ooze with her all the time, but since I have seen it a few times this week, and never before, I decided to investigate. The books we bought are not helpful, and I have not been able to find anything about this yet - which probably results from the fact that I have no idea what I'm looking for. <I'm a bit concerned about you saying the pH and ammonia are at "safe" levels, because earlier on you've said ammonia was "almost nil". Let's be crystal clear about this: any ammonia or nitrite other than ZERO is dangerous. Period. Especially for Mollies. So these are likely stress factors. If the pH isn't at 8.0 and sticking there, the pH variation is another major issue. Either of these issues could be causing general ill health, and from the sounds of things we're dealing with that.> I'm keeping my fingers crossed that you will reply that it's something normal, or at least fairly harmless, but I didn't want to take a chance on losing this Molly also, not to mention the babies she is carrying. Thank you for your help, Hannah <Hope this helps, and good luck with the babies, Neale.>

Keeping/Breeding Saltwater Mollies 3/19/08 Hello, <Hi> I have learnt many things on this site and it has all been helpful. I read the article on mollies and saltwater and how to acclimate them although I was just wondering if it is much more difficult in the marine tank. <Not really, standard SW maintenance and they should be fine.> I used to have mollies years ago but got away from the tropical fish and bought cichlids. I have now got a 55 gallon cichlid tank, a 90 gallon saltwater tank, and a 25 gallon saltwater tank. Once I noticed (on this site) that mollies can do quite well in saltwater I was shocked at first since I had always seen them as freshwater only fish. <Actually in my experience mollies do worst in straight freshwater, I have had much better luck keeping them in brackish and marine conditions.> Sorry for the rambling but here's my question. Will they breed just the same in the marine tank or will the brood numbers be less/more? <Pretty much the same, amazing little creatures.> Thank you in advance. Mike <Welcome> <Chris>

Re: Keeping/Breeding saltwater mollies 3/19/08 Hi, thanks for the very quick response and good to know they are easier in marine tanks. <Welcome> I think I am going to go with the 25gallon tank I have setup which currently but only for today has a damsel in it. I had to remove him/her from my 40gallon tank since he killed my yellow tang and a couple others and yes bad move anyways on having a tang in a 40gallon). <Yes> I have been told my setup is not the best. I have upgraded from the 40gallon to a 90gallon and have 1, going to be 2 fire clowns, 1 sally light foot crab, only one black turbo snail, going to get more sometime, 1 jewel puffer, <Not familiar with this common name but assume it will eventually eat any snails or crabs you have in the tank.> 1 neon blue velvet damsel and a couple green star polyps. The biggest fish in the tank is the puffer which is about 2.5 inches long. The last time I did try mollies in saltwater they only lived for about a day then died, did I most likely acclimate them too quickly? <Most likely, although they are generally pretty tough.> And what type of molly thrives best in marine water; reg. black molly or will any type work? <Any type of true molly should be ok, but be aware that you may see platies or even swordtails labeled as mollies, and these are strictly freshwater fish.> Thanks again, Mike <Welcome> <Chris>

Pregnant Molly, need more data, patience urged 03/19/2008 Hello- I have a female orange Lyretail molly whom I believe is pregnant. Her belly is large and she has dark spots on her belly. She has had the spots for about two weeks now. She will eats some food and then spit it out, she also sometimes "twitches" and acts a little crazy. She also seems to poop quite a bit. Is this all normal? Is it a sign that she will give birth soon? Thanks, Melissa <Mmm, possibly... Do please read here: http://wetwebmedia.com/FWSubWebIndex/mollyreprofaqs.htm and the linked files above. Bob Fenner>

Mollies, pg, no babies? 3/3/08 My mollies are pregnant. They were due a week ago but I don't see anything. What do you think is wrong or happened???? <Baby fish probably got eaten. Also, the mothers will miscarry if stressed (e.g., by being put in a breeding trap or left in the same tank as the male). Female mollies should be isolated from the males when they are pregnant, in tanks with floating plants so the babies can hide when they are born. Please read here: http://www.wetwebmedia.com/FWSubWebIndex/fwbrdgmonks.htm Cheers, Neale.>

Black molly fry 1/27/08 Hi Bob, I have been looking at you website but I am still having trouble locating an answer to my question. My mollies just had 18 babies the other day. We figured she was pregnant but made no move to take her from the tank with the rest of the fish. We have a 55 gallon tank with 3 black mollies, 3 red wags, 2 sunburst platys, 6 neon tetras, and 5 zebra danios. Now we have just added those babies. My question is is how long does it take for a fry to get about an inch long? Do you have some kind of growth chart for fish? Thank you, Misty <The speed at which fry grow depends upon how much food they get and what the environmental conditions are like. For best results, they should be kept reasonably warm (25-28C) and given 4-6 meals per day, though those meals shouldn't be so big that water quality suffers. Water changes every few days, not less than every week, are also important because high levels of nitrate inhibit growth rates. Related to this is a key factor with Mollies -- the size of the tank. When kept in cramped, overcrowded conditions Mollies grow slowly. Putting the fry in a breeding trap, for example, is never a very good idea with Mollies. Commercial breeders keep them in pools rather than tanks. Under good conditions, Mollies will be about 3-4 cm long after three months, females typically growing a little faster than the males. Cheers, Neale.>

Formation of Lyretail in Mollies 1/1/08 I have a Lyretail Molly that had fry a couple months ago. She was already pregnant when I purchased her so I have no idea who the father was. I'm wondering how old the fry are when they develop the Lyretail? Thanks, Deb <Hi Deb. If the father wasn't a Lyretail, then the fry might not be Lyretails either. Aquarists wanting to breed a specific variety of Molly, or indeed any other fish, MUST always purchase virgin females. While some (the better) retailers will sell these, most do not, and you'll need to get them through online traders, fish clubs, fish auctions, and so on. Once you have some virgin females, you can carefully mate them to the specific male Molly of your choice. So given this, the best thing is to simply sit back and enjoy whatever fry you get. They might not be pure-bred Mollies of any one variety, but I'm sure they'll be lively and fun to watch. Cheers, Neale.>

Mollies... repro., gen. 12/31/07 Thanks for all of the help but I just thought of a couple more questions. When you buy fish at the pet store some people say that they are most likely pregnant; is that true? <If males and females were mixed, then yes. The best aquariums stores keep male and female livebearers apart, but unfortunately less sophisticated stores do not.> Do you happen to have a couple pictures of male and female mollies? <The top two photos of Mollies on this page are males: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm It is REALLY easy! Seriously, if the anal fins of your fish all look the same, you probably only have one sex. Make sure you are looking at the right fin for a start. It's the unpaired fin on the bottom of the fish, close to the anus. On a female, the fin is obviously triangular, just like the anal fin or any other fish. On a male, the fin is a long, narrow, tube-like structure that is bent up against the body most of the time. When the male attempts to mate, he pulls the anal fin forwards, effectively forming a structure like a mammalian penis.> I keep on looking at the anal fin and I just can't seem to get it. <Look closer...> It all looks the same to me. <Really...?> Some people say that all mollies are aggressive, but when I watch my fish only one of them (the long one) is aggressive. <Male Mollies vary in aggression, but at their worst can be very troublesome.> What fish are compatible with Dalmatian mollies that I can get at my local pet store? <Mollies are generally easier kept in salted water at SG 1.003 upwards, so choose things that tolerate salt. Guppies, Orange Chromides, Monos, Scats, Archerfish, Violet gobies, Bumblebee gobies, Colombian shark catfish, and so on would all make superb choices. Mollies also do well in marine aquaria, so that's always an option! Avoid fish intolerant of salt such as Gouramis, barbs and tetras. Cheers, Neale.>

Pregnant Potbelly? 11/19/07 Hello, So we just bought a few mollies and some goldfish. Over the last couple of days we have noticed that our Potbelly Molly is getting rather large in the belly. We are thinking she is pregnant and really are not sure. I have attached a picture and was wondering by looking at it can you tell me if she is indeed with babies? Any help you can give I greatly appreciate... thanks. Laura <Difficult to tell from that photo because it isn't in focus. If she's simply gravid, the body will swell only slightly. If she has dropsy, the skin will be stretched such that the scales will stick out from the body, creating a pine-cone-like appearance. You may also notice a lack of appetite, reduced activity, and inflammation around the anus. Dropsy is common in Mollies because they easily become sick. Mollies are sensitive to poor water conditions. They need a high pH (7.5 upwards), lots of hardness (ideally 20 degrees dH or more), and little nitrate (less than 20 mg/l, ideally 0). Kept in freshwater tanks they are much less hardy than when kept in brackish water. Since you have them with Goldfish, they are presumably not in brackish water, and Goldfish are veritable nitrate factories, so water quality may well be insufficiently good. Check the water chemistry and nitrate level. Do read out Molly article and related FAQs -- http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm . Cheers, Neale.>

Pregnant Black Molly 11/16/07 I have a black molly who, after reading the many other postings, I'm sure is pregnant. She's VERY round and over the last few days her behavior started changing. She hung out at the top of the tank (20 gallon) and then she chilled at the bottom. My other Molly, a Dalmatian, would hang out with her. <Hmm... female mollies may well hang out in groups. But male mollies harass female mollies, regardless of them being pregnant. So if that other molly is a male, better believe he's annoying her.> Now she's doing hand-stands (for lack of a better description) and I don't know if this is normal. <Most certainly is not!> She looks very big and the bottom of her belly is showing whiter like the scales are stretching. <I fear this is not pregnancy, but bloating. Many causes, and in the case of Mollies these tend to be three-fold: wrong water chemistry, high levels of nitrate, and lack of plant matter in the diet.> She doesn't look like she's "floating belly-up." She looks like she's holding herself down and standing straight up (tail-up) in the corner of the tank. IS she pregnant or is she about to die? <Suspect the latter.> I don't know what to do. The rest of the community (the 1 Dalmatian and 6 platys are staying away from her on the other side of the tank... thank you, Kelly <Do read the article about Mollies, here: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm , and act accordingly. Cheers, Neale.>

Molly Fry -11/14/07 Hello Crew! After conquering the black moor, I decided to move onto the black molly hybrid. I have a twenty gallon brackish tank with four mollies (three female and one male). The tank is approximately two months old, and has been cycled via help of the common milfoil, java moss, and time. So far, the water tests have been exceptional in general. Here's the problem. Besides the four adult fish, I have 21 brand new molly fry. They are currently one week old and in a well circulated breeding net. What is the right size for the reintroduction of these fish back into the aquarium? Please let me know my best options, and also please direct me to more information on other fun plants to grow in the tank! (Who knew that live plants added so much?) Thanks, Megan <Hello Megan. Rearing Black Molly fry isn't too difficult, though there are some things to watch. Yes, the parents can eat very small fry. But if you grow the fry on for 3-4 weeks, they should be easily big enough to go back into the tank with their parents. To get good growth, feed the fry often but small amounts. Experts recommend at least 6 meals per day! This obviously means you need to give tiny amounts each time, or water quality will plummet. If you decide to keep the fry in a large breeding trap (certainly do-able, if not as good as a breeding tank) be sure and put some floating plants in the breeding trap. This helps give the fry shade, so they don't overheat. Lots of plants work well in slightly brackish water. Almost anything that does well in hard water can be expected to do well at SG 1.002-1.003. Cryptocoryne wendtii, Anubias nana, Java fern, Vallisneria spiralis, Elodea, and the Indian fern Ceratopteris are all good choices. As you've spotted, plants have a great impact on aquaria, especially breeding traps. They give baby fish a place to hide, helping you rescue them. Plants also get covered in green algae and other microbes, and baby fish love to eat all this stuff. Cheers, Neale>

Lyretail Mollie with excessive finnage 10/1/07 Hello, I love your site and return to it daily to learn more and more about my addiction to fishes. <Ah, good> I bought 4 Lyretail Dalmatian Mollies this year and placed them in an established two year old 29 gallon tank. One Molly has fancier bottom fins than the others. In fact I cannot tell if it is male or female. I have attached 2 images and hope you can help me figure this out. The yellow spots on the images are from the cheap dig camera. If these pictures are too blurry I could keep trying for another image. <Is a female, but very interesting that the pelvic fins origins seem so set off... one so anterior than the other> Thank you again for all the information and tips. <Welcome! Bob Fenner>

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