*SICK*I bought what was supposed to be an oto it was in a tank with otos. Looked very similar until i got him home and noticed a small pink patch on his head. Now in 2 month he has went from barely an inch to almost 4 inches and turned completely pinkish yellow. My ph, amonia, nitrates, and nitrites are all perfect. He digs up my plants, pushes decorative rocks around, and bullies other fish. Don't know what to do? I only have a ten gallon and would like to uprade in future but what to do for now.