My father has a 200 gallon tank. whats in it are oscars and red devils. not too long ago some of the fishes had rashes on them and now cleared up its been prob about two weeks now and how the rash was treated was using aquarium salt. Right now what is weird is that almost all the fishes are huddled up to one corner of the tank and has been doing that for days. I have never seen anything like it. One of the fish is swimming side ways looking like he might be a gonner. I dont know whats wrong and what to do to help these fishes. any one has an idea or experience anything like this?