My betta(Charlie) has a little, I don't know, half cenimeter squared area at the edge of his tail that looks like its, well, crowntailing. He is a halfmoon. I never even considered it to be fin rot because he is still super active, there are no cloudy white areas on his tail, and he still eats like a pig! I just ignored it until i thought about the possibility it could be fin rot. Do you think it is?