I just put a hippo tang in my tank after 4 weeks in QT. He looked pretty good and was eating well the whole time. After two days in the DT he is eating like crazy and swimming all around. I noticed there is something white on his fin. It is not a bunch of little white dots like ich, but it is a decent size piece of something that looks like cotton. He is only about two inches and moves so fast I can't get a good pic. What should I do. I feed with selcon and garlic once a day. Any help would be greatly appreciated.