Bennie, your report is very puzzling indeed. There seems to be no rule, except: The sex-ratio is not dependant from different water-values. But scientific experiments have shown: it is. Only on a statistical level, however.
So, my explanation for your puzzling experience is: your numbers are too low. If you breed extensively, only growing-up a few offspring, you will never reach a level of statistical relevance. Low pH or a high degree of humine material does not guarantee you only or many males, vice versa with females, it only increases the statistical probability of having males (vice versa for females). Maybe that your 50:50-success with linkei was due to the fact that this spawn was more numerous than others (which is often the case with linkei). Therefore, in case of intensive breeding the statistical forecast should be more secure than in the case of extensive bred small spawns. Here, the outcome may seemingly refute that statistics, but factually it doesn’t. It only shows that you did not reach the level of statistical significance.
Well, I am not sure. This is only my attempt to explain your puzzling experience.
The
PAROSPHROMENUS PROJECT
