Yeah, I've called my fish dumb out of frustration because they do some pretty dumb stuff. But it's not out of anger, because I know that bettas are one of the most intelligent species of fish there is! So I understand what you meant, puddin. I have 3 tail biters of my own that I can't do anything about unless I just gave 2 of them away and had one in my 10g tank. Just give him time like everyone else said, hopefully he'll stop.