I have a 55 gallon tank with some guppies, neon tetras, cories and cherry barbs in it. What temperature should I set my heater to? The pet store where I bought my fish just says 26C for most of the tropical fish. I had my heater set to 25C, thinking that 26C or higher would cause an algae bloom. But now it looks like my fish are starting to get ich and I don't know if it's because of the cold water or the recent heavy cleaning I did, which caused ammonia levels to spike. I don't see any white spots on my fish, but several of them are rubbing themselves on the substrate. At first it was just one cherry barb doing it, but now I see my cories doing it too. I don't know what I should do. I started reading about ich and it seems the cure uses some serious chemicals that can stain my tank. Sorry about the two questions in one, but if anyone could advise me about the temperature or the ich, it would be greatly appreciated.