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Re: Spawning A. Hongsloi



You are right, Ed. The temperature sensitive period starts at fertilization and
extends to 35 days post spawning. Fry transferred within the first 72 hours had
sex ratios that correlated with the temperature they were put in. After 72 hours
the ratio varied linearly until day 35. After day 35 the fry sex ratios were the
same as that of the spawning temperature.

To me it seems better to just keep them at around 26C (79F) all of the time and
not worry about any linear change in the 50/50 ratio you would get by changing
the temperature after spawning.

Mike Wise

Ed Pon wrote:

> Mike wrote:
> >Rmer's studies on temperate vs. sex ratio show that 81.5% of each spawn
> >kept at
> >pH6.5 and 29C (84F) (close to Michael's suggested temperature and Matt's
> >pH)
> >turned out to be males. If you want a lot of males this is the way to do
> >it. Then
> >again you could lower the tank temperature to 26C (79F) once the eggs are
> >laid.
> >That should even out the sexes.
>
> >From what I remember of Romer's study, sex is not determined immediately,
> but can be skewed some time after hatching by the ph and temperature.  I
> don't know if there is any information in how long the fry need to be
> subjected to a given temperature and ph and at what age to affect the sex
> ratios.
>
>
>
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