# Guppy female-to-male color change



## sb483 (May 29, 2006)

Just something interesting I thought I'd share: If you've kept livebearers you may have seen a female switch over to being male; I once had a small tank with 3 female platies, one started getting skinnier, and after a week it was 2 females and 1 male.
I currently have a 10-gallon with guppies. The female guppies have silver tails, the male guppies dark red tails (and silver fins). One large female guppy with a bright silver tail started developing a gonopodium, and just today I noticed that the white tail is turning a shade of crimson. It'll probably be dark red like the other males in a few days.
Just thought it was neat


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## JanS (Apr 14, 2004)

That's an interesting topic, and there are two totally different sides to it. The majority say livebearers can't change sex, and a few say they can.

Here's one quote saying that they do not change sex that makes the most sense to me, but I don't have anything to back up either side of it, aside from the fact that I've never seen any of my livebearers change sex.


> No livebearer can change sex, their is no evidence in any papers saying other wise.
> 
> What it is, like you say a "late bloomer", If they are are around very dominate males the young fish is capable to stay immature and gain extra size and strength, these are the very best fish in nature. most livebearers mature between 3-6 months but "late bloomer's" i have seen take a year to mature.


Does anyone else have any thoughts/experience on the subject?


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## freydo (Jan 7, 2006)

a friend of mine swears that one of his swordtails switched teams, and he breeds fish, so i'm fairly confident it happened. so i don't know about the "late bloomer" theory being all that correct.

reptiles have been known to switch as well, if i'm not mistaken (please correct me iffin i am wrong). so why wouldn't it be conceivable that it can happen to fish?


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## JanS (Apr 14, 2004)

freydo said:


> reptiles have been known to switch as well, if i'm not mistaken (please correct me iffin i am wrong). so why wouldn't it be conceivable that it can happen to fish?


It definitely happens in fish too, especially marine fish, with Clowns being a big one, but with FW livebearers, most say it isn't possible, and a few others say it is.

I know that temperature plays a big role in gender with most live bearers, but I think that's at a pretty early stage - maybe while they're still in the mother?


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## ed seeley (Dec 1, 2006)

If I remember rightly Xiphorous livebearers have chromosones to determine sex. In fact they have three different sex chromosones, X and Y and W!
These are present in cultivated hybrids from the different parent species and can lead to all male broods.

If there are sex chromosones then other factors, such as pH and temperature shouldn't have an effect on the sex ratio or sex changes. I've heard, not experienced, that these may be either late blooming males in some cases and overly dominant females producing male secondary sexual characteristics in others, with I'm sure a smattering of other things too!

As Jan said many fish change sex during the course of their lifetime, but these are almost exclusively, AFAIK, marine.


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## Mad Dog (Mar 3, 2007)

From what I have learned, both from reading and on forums...some of which have legitimate experts on certain subject...livebearers can and do change sex...however the debate is created because they change at such a young age. So young in fact, that it is almost impossible to sex them correctly anyways. From what I gathered, it is one of those "if I cant see it, I cant believe it" type situations. Obviously, I am not a scientist or hold a PhD in biology, so this is just what I have read and seen thus far.

There are quite a few fish that change sexes, including a larger number of saltwater fish such as clown fish. The big difference with live bearers is that I believe they cannot change sex in the middle of their lives (also another debated topic apparently). To put it simply, fish who do change sex do so because of the ratio between males and females just after birth or relatively soon in their life. It is also true that the tank conditions and water chemistry may play a part in what sex a fry is going to be. For example, in the guppy side of things, males are probably the most desired due to their colors and what not so a fish farmer can influence that outcome by changing the water temp. This information was written in an article within a popular aquaria magazine....if I can find it again, I will pass on more information on this. 

While on the subject of debatable issues within the hobby, it is also commonly stated that livebearers benifit quite a bit from the addition of salt to an aquarium...which in many cases, is contradictory to the semi-recent debate and trend which leans towards never using salt in a freshwater tank ever.


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## bristles (Mar 7, 2006)

I don't know about guppy's but I have had a female sword (large in size & post fry bearing) "turn turtle" so I have to come down on the side of saying it is possible, just my opinion


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## sb483 (May 29, 2006)

The above post certainly sounds contradictory to the late-bloomer theory (I'm assuming giving birth to fry is an indication of having reached maturity).
The platies I wrote about in my first post were adult-size as well. The guppy that just changed sex and fin-color, however, is juvenile, and I can buy the late-bloomer thing with he...him


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## ed seeley (Dec 1, 2006)

bristles said:


> I don't know about guppy's but I have had a female sword (large in size & post fry bearing) "turn turtle" so I have to come down on the side of saying it is possible, just my opinion


Did this female become a functional male, or did she just show male secondary sexual characteristics? It has been hypothesised that females that are old and whose ovaries no longer function can lead to the fish showing male characteristics, but not becoming functional males producing sperm.


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## Mad Dog (Mar 3, 2007)

> Did this female become a functional male, or did she just show male secondary sexual characteristics? It has been hypothesised that females that are old and whose ovaries no longer function can lead to the fish showing male characteristics, but not becoming functional males producing sperm.


This is also a very common situation for many cichlids in that a male may keep the female coloration or vice versa depending on its status on the dominance 'totem-pole' in a tank. Conversely, it is also possible to find a female who has changed its coloration to mimic a male when it is the most dominant fish...although in each case, they are still the same sex as far as functionality goes, they just have the wrong colors displayed. I realize that this doesnt help when looking at livebearers alone, but I thought I would bring it up to help support the ideology here.


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