[Peter Finke]

Jacob, I saw your last mailing just after having finished my reply to the former. You think in the right directions, certainly. But there is no germ-free aquarium. Tests say that the tank with the least germs contain more germs than any blackwater in nature! Your arrangement with peat filtering and almond leaves is a quite good one, but in cannot exclude the germs fully. In fact, there are certainly rather many of them.
So, as I recommended at another place, buy one of those measuring kits for germs. Then you will see.
But don’t resign: If one is conscious about that problem, one has done a big step from “normal aquaristics” to advanced Parosphromenus-aquaristics. Healthy adultParosphromenuscan stand by far more germs than they experience in nature. But adult only! Our aim is always to breed them. The problem are the eggs and the very young fish. Especially the eggs. They are very sensitive to too many germs. But again, don’t be disappointed. The harder species (as filamentosus, linkei, paludicola, even nagy)will happily rise their eggs and young if you pay a little attention to that question. The pH is the most obvious means to do that. And there you are on the right track, with peat filtering and almond leaves. And regular water change, of course. But once you have got the right turn, even the water change could be reduced (not to nil!).