I bought myself some fish three or four months back, a platy and 4 danios to start with. I recently bought another platy and two zebra danios and switched to a bigger tank about a week ago (19litre) although it does not have a heater as I was assured they were temperate fish. I have had the new platy and two zebra danios for about two weeks now and I noticed today that one of the danios was dead and stuck to the filter. I removed the dead fish and did a water change. However, the other zebra danio seems a bit listless and looks as if his scales are slighty raised, or that there is a translucent coating on them. The other fish all seem fine. Does anyone know if this is a problem and if I should remove the other zebra danio? Thanks :)
