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scruffy
10-09-2007, 05:28 PM
Why do some fish take so long to develop a gonopodium? Only a couple weeks ago, I discovered that the majority of my 3 month molly babies were boys. In more recent batches, I could tell at about 4 to 6 weeks and the second batch clearly had the same mom and dad. Also can a male platy father children before it gets the gonopodium? My variatus babies were still having babies when the only obvious male in the tank (they had ever known) was not paying any attention to them.

S

Atlantis Child
10-09-2007, 06:04 PM
Dunno, but did you know some female platies have a gonopodium? Smaller, but still there. Strange but true.
And I know this personally, cuz one of mine with one had babies.

Sorry...off topic.


Also can a male platy father children before it gets the gonopodium?

Rather doubt it.


- Atlantis

CAF
10-09-2007, 07:40 PM
Why do some fish take so long to develop a gonopodium? Only a couple weeks ago, I discovered that the majority of my 3 month molly babies were boys. In more recent batches, I could tell at about 4 to 6 weeks and the second batch clearly had the same mom and dad. Also can a male platy father children before it gets the gonopodium? My variatus babies were still having babies when the only obvious male in the tank (they had ever known) was not paying any attention to them.

Scruffy,

Female livebearers can, under the correct conditions, change sex and become males. Most often this occurs when there are more males than females. Unfortunately once they change into males they can not go back. However, this can explain why some of Atlantis Child's platy females showed a gonopodium but gave birth. Once there the "female" gives birth, she will most likely finish the metamorphis and become a true male and no longer be able to give birth.

To answer your next question, males with unformed gonopodiums may still be able to impregnante a female if the gonopodium has formed enough for the sperm duct to be present. It would be by no means an easy feat, but still possible.

scruffy
10-10-2007, 12:11 AM
That is amazing! I've heard of some fish doing this in the wild, but didn't think it could happen to mine. Is there a known tipping point where there are too many girls and some become boys? I have always heard that for livebearers, there should be at least a two to one or three to one ratio of females to males. I can see how one could get into the rut of buying more and more females to keep it balanced. Kind of like a three legged stool.

Are there other water conditions that might affect gender?

S

CAF
10-10-2007, 12:22 AM
I can see how one could get into the rut of buying more and more females to keep it balanced. Kind of like a three legged stool.
LOL It definately seems that way at times



Are there other water conditions that might affect gender?
Honestly I am unsure. I believe so, as all of my female Heterandria formosa became males over the last month or so. It was my tank at work and the Nitrates got really high because I didn't have a test kit... since remedied...
I'll try to find out. Give me a couple of weeks, I'll hit some people I know in the ALA (American Livebearer Association).

scruffy
10-10-2007, 03:58 PM
Thanks CAF, I am interested in what you find out. You may be onto something about the nitrate. It was a bit high a couple weeks ago.

CAF
10-10-2007, 04:10 PM
Thanks CAF, I am interested in what you find out. You may be onto something about the nitrate. It was a bit high a couple weeks ago.
I did find a scientific paper published showing higher temperature cause the sex change into a male.

You can view it here:

http://content.karger.com/ProdukteDB/produkte.asp?Aktion=ShowPDF&ArtikelNr=100035&Ausgabe=232896&ProduktNr=231547&filename=100035.pdf


I'll keep looking for other reasons and let you know.