Re: Sex ratios

[Pete Johnson <petej@wordsanddeeds.com>]

>I've read that in fact the sex is determined not at conception but in
>the first 2-3 weeks of the life of the fry...

Uwe Romer and Wolfgang Beisenherz studied the effect of temperature and 
pH on 33 species of Apisto fry and found that during the first month of 
development low temperatures (below 76 F -- the "cool" test tanks were 74 
degrees) produced more females. Low pH (5.5 and below) produced more 
males, but had less influence. If you want balanced sex ratios, try to 
keep your tanks at 76 degrees during the first month of fry development. 
That may be a challenge in Florida. :-)

>Whewwww is anyone up for writing a book???????

Uwe's book is at the publisher's, according to David Soares.


Pete Johnson     ||     Two approaches to the same problem:
San Jose, CA     ||     flying fish and penguins.