[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Sex Ratios

Mike Jacobs writes:

>My A. cacatoidies (watch my spelling all the time....unintentional I assure 
>were spawning very  successfully at a pH of oh about 7.7-7.8 and the the sex 
>was 98% males

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.

Since Mike lives in Florida, his high percentage of male fry probably has 
more to do with heat than pH.

My water parameters slightly acid -- typically 6.8 -- and about 78 
degrees and my sense is that my fish produce generally even sex ratios, 
though I often sell or trade fry before they are sexable.

- ---------------------------------------------------------
        If wishes were fishes we'd all have ponds

Pete Johnson  /  San Jose, CA  /  petej@wordsanddeeds.com
- ---------------------------------------------------------