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Re: only male fry

It appears that your friends are rearing their fry in water that is too warm. Römer & Beisenherz (1995 & 1996) found that most apisto species produce mostly males when the fry were reared in temperatures above 29ºC/84ºF. Apisto tend to have equal sex ratios when the fry are raised for the first 1 - 2 months at 26ºC/79ºF. In this respect, the temperature at the time of spawning is not as important as the temperature at which the fry are reared for their first few weeks.

BTW I think there was a typographical error in the answer you received about ppm. At low levels of total dissolved solids, 1 ppm TDS roughly equals an electrical conductivity of 1µS (microsiemen). 1 mS (millisiemen), or 1000 µS, roughly equals 1000 ppm. It is not an unusual mistake on emails. Many do not know how to type a micron symbol (µ) & mistakenly use an "m" instead. The use of an "m", of course, represents "milli" in metric units.

Mike Wise

Dániel Gergely Faragó wrote:

Hi All again,

I think you shouldn't encourage me again to write. So I would have another question.

I have some friends, who breed apistos. Lately they ran into a huge problem. The whole fry became male. It happend to A. atahualpa, and A sp. "Rio Mamore" (or A. maciliensis according to Römer). There were no females and nothing happend when they adjusted PH or other water conditions. This happend now for twice or three times. So what did go wrong or what can they do to have females as well?


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