Well I do put aquarium salt in my tank after each water change. Someone at the pet store told me that it woundn't hurt any of fish but that some require it and it helps keeps them healthy, so I just use it. At the pet store they had gouramis and glass fish in a big tank together. I haven't noticed anything wrong with my glass fish, and he seems to be doing very well thankfully. But on the other hand, all of my fish (except one) seem to be improving. I am going to leave the heater cranked up for a total of two weeks. But my black mollie now has brozne colored patches on him. I might move him to a another tank by himself. What is this and how can I get rid of it? Will this affect the other fish in the tank?