about curling around the leaves... he might just be playing with it... or itching itself. I think you may have fin rot... otherwise, in my own experiences, if you have other fishes in the same tank, then they may be nipping at the betta. My betta was nipped several times before I noticed that the littler fishes were attacking it. Bettas usually don't attack other species of fish, however they will chase and scare away the fish. Seperate him from the other fishes with a divider or just put him in a bowl.