Hello everybody,
this is a very interesting topic indeed. I have more or less the same water conditions in every tank: small bag of peat granules; beech leaves and a piece of Catappaleave; around 23°C;
With P. harveyi I get very balanced sex ratios up to now. With some Betta on the contrary, I always have a lot more males.
I tend to agree with Richard Brode (IGL), who states that this could be a general problem of extensive breeding: males grow faster, are more aggressive and therefor get more food. So they starve out the females in a very early stage (which one doesn’t realize) and you end up with all males.
It would be interesting to hear if someone who breeds intensively, really gets well balanced sex ratios.
Greets
Martin