I think my glolights, my dwarf gourami, and my platys have it. I lost three fish all in one day. My shark, a platy, and a ghost shrimp!!! I think I way overfed. I don't ever know how much to feed them. That whole how much they eat in 5 minutes thing just doesn't work for me. Don't ask my params, I never check. I do water changes at least once a week and gravel vac at least every other. I will normally vacuum the tops of the gravel when I do just a weekly water change. My water was super cloudy yesterday morning whenI woke up after being completely clear the night before. Could I have overfed them that night that much?