Re: Sex ratios of nijsseni based on pH

[Mike & Diane Wise <apistowise@bewellnet.com>]

Cory,

The only major effect that pH has on breeding A. nijsseni is the number of viable eggs (= potential # of fry) you'll get. Temperature affects sex ratio. Please refer to my reply to Doug Dunlop's 03 Feb 1999 message, "nijsseni temperature", for specific results of temperature/pH values on this species. These results of Römer's are are based on a large number of nijsseni spawns:

pH 4.5/23º - 14 spawns, pH 4.5/26º - 20 spawns, pH 4.5/29º - 12 spawns
pH 5.5/23º - 12 spawns, pH 5.5/26º - 24 spawns, pH 5.5/29º - 18 spawns
pH 6.5/23º - 13 spawns, pH 5.5/26º - 24 spawns, pH 6.5/29º - 16 spawns

I'd say this is statistically very definitive. Any reports to the contrary seem to be anecdotal by comparison.

Mike Wise

Cory and Susanne Williamson wrote:

 I have read conflicting information regarding the sex ratios of A. nijsseni produced at varied pH levels- can anyone tell me what the effect of pH on the sex ratio actually is. Cory