Gender switching guppies...

[Calcifer10000]

I'm just curious, does anyone know if the ability for guppies to change gender a natural one for them?

Interested to hear your thoughts!

 

[tkos]

I know certain fish like clownfish change change gender, or at least their gender is set by their environment. Some reptiles can as well, but I haven't heard that guppies can do it as well. If someone has a reference that would be interesting to read.

I don't believe that they do, though, or fish stores wouldn't bother separating them into different tanks.

 

[Allivymar]

Guppys really can't "sex change".

That being said, folks have seen incidences where they've removed all the males, and some females appeared to "switch". One of 2 things have happened there. Either some of the females were actually immature males, or the X and Y balance is thrown off during the embryonic stage, and an apparently XX female actually has some Y genes hiding in the mix. In either case, they haven't actually changed sex as they have the right genes from the beginning.

Theres a bit of info on the XY issue on this page: http://biol1.bio.nagoya-u.ac.jp:8000/sexuality.html

 

[Fruitbat]

Some of the older aquarium fish texts make the claim that certain freshwater fish (i.e. Mollies, Platys, Swordtails and Guppies) can change gender. However, I have not been able to find ANY recent references to this ability. I suspect that true sex changes in freshwater tropical fish are unlikely.

 

[tkos]

Perhaps what is happening is the fact that many live bearers can be impregnated once and the females can hold onto the sperm for use later. This might give the illusion that they are getting impregnated without a male around.

 

[Calcifer10000]

Thanks for your thoughts, everyone!

The reason I asked is because this gender changing thing happened in my tank and I was wondering if it's just a kind of genetic accident or something. It actually didn't happen when I separated out my males and females (I had 2 males and 10 females from one mother guppy). What happened was I took one of my females and put it into the male tank where it got harrassed by the males constantly. After about 2 weeks, it began looking funny: ie its anal fin had split and its tail was turning orange. Now, it's a complete male. I swear: it looks almost exactly like the other males, complete with a male anal fin, bright orange tail, dark body with pretty colored stripes, and it chases females too.

I just thought that was interesting...do you think it was due to a "if you can't beat them, join them" response? (I do think this only happens when they're a certain age, though, I think when they get past a certain stage in development they don't change anymore.)