# Molly Sex change



## kittykatydid08

I got a couple of dalmatian mollies that were very young. We put them in a 10 gallon tank with other older mollies and there was an older balloon male and two balloon females. As they got older we realized that we had a male and two females of the dalmatians. This was a couple of months ago. One of the females died and that left us with a male and female dalmatian. 
As of today we were looking at them and realized that they are both males. I know for a fact, or thought I knew for a fact that there was one of each but now that has changed. Can they really do that and if so is the female who changed fertile?


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## humdedum

As I've read it, some mollies can indeed develop a gonopodium as they grow older. However, they cannot impregnate a female or breed as a male would.


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## kittykatydid08

This one thinks he can . . . I don't know it was very disturbing to find out.


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## TheOldSalt

Sexchange in mollies is very common, and contrary to a weird common belief, the new males are usually perfectly fertile and functional. ( which is kinda the whole point of their doing it in the first place. ) This happens in many other kinds of fish as well, with varying degree of fertility. Guppies do it sometimes, for example, but are usually sterile. Platies and swordtails do it all the time, but they have an extra sex chromosome made just for this which doesn't activate until late in life, and those fish are generally considered as late-bloomer males that were always males, even though they looked like females.
Saltwater fish? Good grief; sexchange is starting to look like the rule instead of the exception. Most of them apparently do it.


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## humdedum

Thanks, TOS, I wasn't completely sure as I've only read about it in a couple of books. I've heard about so-called late blooming swordtails.


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## fish1

as been mentionend they are late-bloomer males. Livebearers do not change Sex


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## kittykatydid08

That explains alot. Thank yall so much. My family is disappointed cuz we named them names from Mulan and now we need to change the one who changed to a boy name.


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## TheOldSalt

Ah, but some livebearers do indeed change sex, most notably mollies. Over the past, 39 years?... I have had several females which gave birth to live fry only to become males later in life... and subsequently fertilize young females. Lake Peten's P. kykesis is especially good at it. There is usually only one male in any given tankful of fish. Once he dies, the dominant female becomes male. It's pretty cool, if also annoying to someone trying to produce a lot of pretty males.
Yes, I know what you're about to say. You're about to compare them to Amazon Mollies and try to muddy up the issue, but I'll stop you before that mess starts. Even Amazons need viable male seminal fluid ( but not sperm ) to trigger gestation, despite not being picky about the species of that fluid's origin. Putting that aside, my own experiments prove the issue pretty conclusively for me:
I had been trying to cross kykesis with latapinna in the hope of producing something cool. It didn't work out well. All I got was speckled fish. Every now and then I would have a formerly fully functional female turn into a male. Once I got a goofy notion to cross one such male with some pure strain kykesis females from another tank, and the resulting fry were speckled! That's right; the newly minted male's DNA absolutely contributed to the new offspring. There is no way around it-- mollies are capable of actual sexchange. Had they been "amazoning" it, the fry would have been all pure & non-speckled.


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## DTetras2

I'd say that the blooming of female to male occurs when there aren't many, or any, males left in the group. This happened with my female swordtail when my male swordtail sadly died (rest in peace). before he died, the female did have babies with him, which was fun until they escaped past the divider and got eatin  Than the male died somehow, and the female started becoming more agressive and started growing the famous "swordtail" and started to get less plump, so that was a huge surprise to me


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## kittykatydid08

If you think about it, it does make sense. I've just never had it happen until now. . . besides this female was anything but dominant. The dominant female is a balloon molly.


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## fish1

i have 4 female and 1 male swordtail if i remove the male from the tank and going by what you are all saying i should see a female change Sex.


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## TheOldSalt

Well, maybe so, yeah. It's pretty commonplace, especially among larger, older females. Swordtails of course have the extra "W" chromosome along with x & y, and it seems to be what controls this. The tricky part is that you wouldn't be able to tell if it was a true sexchange or simply a lateblooming unless you paid very close attention, took notes, and experimented afterward with breeding attempts.

B the way, a new-male swordtail formed from a very large female can approach six inches in total length and look truly spectacular. I'd recommend trying to induce the change just to see one of these beauties for yourself.


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## fish1

Although it may be possible for some livebearers to change sex I believe when or if it occurs it would be on very rare occasions true sex changes in these fishes are not as common as many people beleve it to be. my beliefs are that there are many young and inexperienced fish keepers that often buy fish from there lfs and not fully understanding whether they have bought true males meaning that they often buy juvenile fish that can often take a long time to sex out some may take a year or moor before they fully develop a gonopodium. 

All livebearers start of looking like females, many new fish keepers believe that there livebearer as changed sex . what happens when a dominant male dies or if it is removed the next one will take its place and develop it’s true gender.
very old females can take on the characteristic of a male swordtail however they can not function as a normal male .

99% of these so-called sex changes are just s. simply a late bloomers
If a sex change do occur with any of my fish I will most definitely know if it is a true sex change or simply if it’s a late bloomer.


I have some very nice xiphophorus pmh / xiphophorus mayae
thay can grow enormous. one of the females have just had fryi hope to do well with them and grow them on bigger then the adults .


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## TheOldSalt

*sigh*

Here we go again. I don't blame you, really; this happens all the time.
( _although my hostility should be easier to understand momentarily_
)
So here it is, one more time:

Since 1972, I have observed dozens of these things. While oftentimes not, some of them have absolutely been cases of fully functional females, that gave birth, later becoming males and subsequently fertilizing other virgin females specifically selected for the very purpose of testing this possibility.

IT HAPPENS. IT REALLY DOES. I DON'T KNOW WHY this is such a difficult concept for so many people to grasp, especially considering how commonplace it is for other fish and even some non-fish.

That's it. I don't know what else I can say. I'm sick of arguing about this all the time. This phenomenon has been well documented several times over the years, so my own say-so hardly matters.
No. I'm not going to go on a link-posting spree. Apparently all the other times I've previously done that have had no lasting effect, so I don't see the point in bothering since it's such a pain anyway.

Just for fun, I'll also mention the affect of unfiltered tanks with dirty water allowing the buildup of hormones in the water which turn ALL the females in a tank into ugly sterile half-males. Guppies exhibit this the most, mainly because they can survive it, I think.


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## Cichlid Man

Just for the record.....one of my neolamp dafodil cichlids changed from female to male, rasing fry in both male and female form. So when it comes to fish anything is possible.....I even had a guppy once that layed eggs (they didn't hatch)


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## fish1

I don’t do cichlids my only interest in fish are the Livebearer family 
Your guppy had a premature birth the eggs hatch with in the womb it is very unlikely for eggs to hatch out side of the womb there are many reasons for this to happen some times the fry can also be a bit premature at birth when given the right conditions they soon recover.


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## kittykatydid08

Thanks guys. I didn't mean to start anything. This female was a female because she got huge and then got skinny at the same time the betta that was in the tank got extremely fat. Needless to say we have moved him out for a while to see how many more babies there are gonna be.


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## fish1

good luck with all your babies your be over run with them soon remember fish tanks can breed almost as fast as the fish,


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## kittykatydid08

Thanks. We already figured that out. My roommate started out with one 5 gallon and now has 5 fish tanks total.


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## Fishy Freak

I have had it happen in guppys, yes fish can change sex from female to male but never from male to female.


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## TheOldSalt

Oh really? Tell that to any clownfish breeder.


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## fish1

how many times have it happen with your guppys did it/they have fry before the change ?


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## Fishy Freak

Ok old salt, I only deal with freshwater so don't know about clown fish, and I guess there are always exceptions.


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## TheOldSalt

Yes, yes there are indeed. If I've learned anything over the years, it's that.


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## Cichlid Man

Fish are very good at adapting to changes in heiracy, hence a dominant female changing into a male or vice versa, just imagine if for your whole life you got told you were a girl...then your thing dropped off....one way in saving the governement millions on sex changes I spose


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## Bill in Clwtr

Just what you guys are talking about has happened to me. A totally full grown creamsicle lyretail Molllie that gave birth to over a dozen fry has changed it's gender into a beautiful male. It went from a normal small top fin into an enormous sail fin. It even has a black stripe at the very end of its tail. It went from the small fin where the fry popped out to a functioning male appendage. He has become aggressive and is trying to mate with the females he grew up with since childbirth from a different mother. I am curious to see what happens next. But all the years I have had platy's and Mollie's this is the first time I have seen this happen.


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## weedkiller

lol reading through this has left me kinda freaked...
imagine waking up next to the missus who has just turned male... AAARRGGGHHH


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## TheOldSalt

Yep, it happens. When you say black stripe on the end of it's tail, do you by chance mean it has a tiny little black "sword?" If yes, then that explains it. The creamsicle is a hybrid, and the swordtailed molly always changes sex.


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