Molly Sex Change?!?

gazza76

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Hi all,
I'm new to this site and would firstly like to say hello to everyone!

I'm new to keeping Fish and about two months ago I brought a Juwel 180 (ltr) from a local store. I have put 6 zebra danio's, 5 sailfin mollies (1 Male & 2 female dalmation and two female silver, the male silver died), 2 very small angels, 6 black phantom tetras (4 female), 3 golden sucking loaches, 5 kuhlii loaches, 1 cory melina and 1 cory julii.

All of these fish are friendly and are sometimes quite playfull, especialy when I attempt to do my water checks (they come up and nibble my fingers when filling the test tubes with water!).

Anyway, as the title says, I think one of my mollys have changed sex from female to male! You see, I brough 3 Dalmations (2 female) and 3 silver (2 female) the male silver died, leaving just the one, rather lucky male to attend to the 4 females. I have had 4 lots of fry over the last 3-4 weeks and am almost positive, that they are from all 4 females.

I was looking in at my fish yesterday and noticed a so called dalmation female, sniffing the rear of the smaller female. I didnt think much of it, until the male chased it away. I then noticed that the little fins at the bottom rear, had become very very small and tight (they were quite large before) and the bottom middle fin was now looking rather like the males gonopodium.

I hear stories that guppies can change from female to male if no male is present (it maybe swordtails) and have heard that mollies can do this too, although the aquatic shops in my area tell me they can and another says no they cant!

I know that this fish was female, but am now really unsure! Please help!!!!!
 
It is sword tails you have heard of I would wager, however the sex change sword tails are not fertile afterrwards.

Could her back fin have just been damaged?
 
Hi Opcn,
I dont think her back fin is damaged as it comes out like the males gonopodium.

It's quite baffling, as I am 100% positive that she is a female, or at least was!!!
 
I have heard this discussion many times before. It may be that the fish wasn't fully developed and just had weird gonopodium. But, IMO, it is totally possible that your fish went through a sex change. I have had a few do the same, yet there is no real explanation that I can find :/
 
http://www.fishforums.net/index.php?showtopic=127711&hl=

How old is this fish? About how big? You can't be certain the babies came from "her" can you? Are her fins clamped? Because when they are, they can appear to be male. Or s/he might be a late developing male. It is pretty much considered impossible for Livebearers to change sex, it's usually late developing males or different looks.
 
It is pretty much considered impossible for fish to change sex

Not to disagree but this is very much a species dependantthing, many saltwater fish in the gobie family can change sex, and many wrasses, anthias, clownfish, and angels must change sex at some point because they are all born one sexor the other.
 
Who was talking about Marines? The topic is in the Livebearer section, and we are referring to Livebearers, so that's what I ment. I changed it to make you feel better though. :p
 
Hey, sorry I took so long to get back. I have no idea how old it is, but have had it with me for about 2 months. It wasnt small when I got it (not big either).

I think it will be one of lifes little mysterys!!!

Thanks for your help guys

p.s. I am 100% certain now, that it is male......
 
I have no idea the science behind it, but I had the exact same thing happen to me about a month ago. I bought a female silver molly, and I was 99% sure it was female.....and the people in the fish store told me it was female. I put her in with 4 other females for a month and everything was fine. I introduced a male into the tank and they went at each other. I thought they were trying to mate, but after an hour of it, I noticed that the females fin was starting to look like a gonopodium. They were going to kill each other so I quickly moved the silver shemalé to another tank, where two days later he/she was chasing around the females and it was definitely a gonopodium, it was moving around just like one and he/she successfully mated with a female.

The silver shemalé molly was about 2.5-3 inches when I got her/him so I would say she/he was full grown. I don't know if it was a late developer or not, but it definitely developed after I got it.

The only thing I can think of is that maybe since some fish stores don't want them developing early and mating they might add some chemical/hormone to stop them from doing so. Once you get them home, you no longer have that chemical/hormone in the water and boom, nature takes its course.

Or possibly even the sheer volume of fish that are usually together in a tank at a fish store would keep the fish from developing because if the fish is sexually mature and it produces fry, then there will be less food for the mom. Kinda like a population control/self preservation until a time comes when it isn't so crowded.

Had anyone ever seen a male molly turn into a female?
 
My bf just gave me some fry that came from his only silver lyretail female molly he had and she is now a MALE!! SHE/HE has been flexing it's new gonopodium at the other females and chasing them. What's up with this?
 
Old female livebearers can take on male characteristics; even to the extent of growing a gonopodium (rather like the way old ladies sometimes get a moustache!), but they're still female, and can't function as a male to the extent of producing sperm or fathering babies.
 
yes but why is she chasing females and flipping her new gonopodium at them?
 
Because she feels like a boy; the male hormones will be overriding the natural behaviour of a female.
 
She will, from now on look, and act, exactly like a male.
 

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