I just lost 4 otos, 3 cory’s and 2 danios to some mystery illness. I checked my PH 7.0, Ammonia 0, Nitrites 0 and Nitrates 40ppm. Today I noticed that some of my fish have a white fungus type of thing on the back of their fins. I treated them with Maracyn and Maracyn 2.
In the meantime, my...