Does Temperature effect sex of fry?

[guppymonkey]

I have had my fry for more than a month now and it looks like they are all female. This seems kind of strange to me, I thought at least a few would be male. I know that temperature affects the metabolic rates of fish but I was wondering if temperature could effect the sex of the fry. Maybe during development in the mother?

 

[Sinuhe]

Is this guppies, swordtails, or something else? I remember reading recently about swordtails, how some factors can affect how many males and females come out of a batch of fry. One of the factors was the space available when growing up. I'm not sure if temperature was another.

Edited to add the link: http/www.soest.hawaii.edu/SEAGRANT/Makai...ai/oct00/3.html

 

[suemack]

don't think its the temperature that affects the male/female ratio guppymonkey - from what Ive read they think it's the pH. I'll have a hunt through my things and see if I can find the article with details

 

[suemack]

hi again - found the article in an old TFH magazine - reporting an 8 month study done with platies


'at a pH of 6.4 to 6.6 the sex ratio was almost 1:1, at a pH of 7.2 to 7.4 the sex ratio was one male to four females'

this was one report in amongst others that seemed to support the theory that low pH produced more males, higher pH produced more females

my tanks are usually about 6.4 pH (rainwater) and I mostly get equal nos of males and females

sue

 

[MAM]

that explains my fry. they look to be all female.