RE: Sex Ratios

[Tom Mroz <tmroz@art-inc.com>]

Interesting.  I have been spawning and raising triple red cacatuoides in 
water in the mid-70's tops, and pH at the high end of 7, and I have been 
"plagued" by very high male ratios.  I had a batch last year of about 50 
that did not have a single female!  Back when I was doing them in softer, 
lower pH water, I was getting almost all females.  I really would like to 
get to even sex ratios - perhaps the low 70's and neutral pH?

Tom

- ----------
From: 	Pete Johnson[SMTP:petej@wordsanddeeds.com]
Sent: 	Tuesday, April 29, 1997 11:21 AM
To: 	apisto@majordomo.pobox.com
Subject: 	Re: Sex Ratios



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.


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        If wishes were fishes we'd all have ponds

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