I just notice this about 2 days ago and it seems to be getting worse. It seems to me it has to be fin rot. My water is great and she is the diva of the tank and always happy. I did a 40 percent water change today which is big for my 20 long. Now she is acting a little goofy darting around. Honestly I think it was over feeding since she hangs up top like betta do. Can this be reversed by cutting back food or does she need meds, I don't have a hospital tank.