So I have a crowntail male betta named Mushu that might be sick. I got him about 2 months ago. He is housed in a filtered 2 gallon hexagon tank and has a heater. I feed him as instructed by the guy from petsmart with 3-4 pellets of "Spectrum" every Monday, Wednesday and Friday. The guy also told me that I only have to clean his tank once every 2 weeks since it was filtered (which I do). The water is tap water and is treated a week in advance with "API tap water conditioner" with 2 drops per gallon. Anyways, about a week ago Mushu was getting a little white on his fin. He was acting fine (very energetic) and I looked it up and thought it was fin growth. Well about a week has gone by and he's about 50% white. It's summer here in Minnesota and its warm, I read somewhere that it could be from it being too hot so I unplugged his heater. I also cleaned his tank last night just in case. I never use soap when I clean it, I just thuroughly run everything under tap water. I'm not sure what to do. He's acting fine, but it doesn't look healthy. Anything helps guys and I really appreciate it. Thanks.