what determines sex?

[aspen]

i invite you to read the following article:

http://www.cichlidae.com/articles/a100.html

i wonder of any of you guys or gals have anything interesting to add, esp, regarding any spawns that have been higher one sex or the other and whether you could explain why you think they were this way. also, have you ever had a fish change sex. what species, and under what conditions.

rick

[mordor]

Romer collected a lot of statistical data on this subject. Conclusions are presented in Mergus Cichlid Atlas.

[Neil]

aspen,
The only Dwarf Cichlid that I know that changes sex is Crenicara punctuatum. However, if you want to get technical, it is theoretically possible that many species change sex in the first weeks of their lives in relation to changing environmental conditions. It is a good bet that sex is determined after the free-swimming stage in Apistogramma. If they are subject to changes in temp or pH at that point they may develop according male or female characteristics.
This is just conjecture, but if a spawn is in cool, 8.0pH water for the first 7 days free-swimming, then are switched to warm, 5.0pH water, they might alter their beginning female characteristics to male. :?: 8O
As Ron mentions in his article, I believe that it is more than the temp and the pH that determines the sex of apistos, but also things like hormones, etc. Additionally the same results have not been shown in the wild as they have in the captive environment. Neil