Sverting: a flood of questions, but of good questions. Mainly of questions that I am unable to answer. But I am rather sure that there are no tests comparing the productivity of females kept at different levels of temperature. “Test” is a strong word. There are nearly no “tests” of many aquarium problems, only experience. Many people exaggerate their own experience to general laws, and that’s a mistake. No, I know of no tests.
As Oodinium is concerned it’s obviously a serious problem of (not only, but mainly) softwater fish. Again, I don’t know whether the relation you mentioned is proved by a enough and sound experience.
Your other question regarding temperature are very interesting indeed, but there is little waht could serioulsy be called “knowledge”. Most expeditions measure temperature, but that are accidental values at accidental times. Probably there are measuring series in other contexts; it would be very helpful imdeed if somebody could advise us on that. I can’t.
But the last thing. My remark on the beginning breeding season did not in the first line refer to temperature but to rainfall. This, the beginning seasonal monsoon raining season, is the triggering factor you are searching for. This is related to changes in temperature, too, mainly dropping temperature, but the main thing is something else: the further reduction of dissolved minerals in the water, that are markedly “thinned out”, and the corresponding increase of solved organic materials. And this again results in a strong increase in microorganism-life which is he food basis for the young fish. Such are the main triggers in the beginning breeding season. Temperature is one factor among others but is probably less important. If so, more by dropping than by rising temperatures. Insofar you are right again.