Speck is appearing to have parts of his tail missing, and although I haven't seen him chasing his tail/swimming in circles, I do not believe it is fin rot. I noticed that in the sticky about betta diseases fin rot is usually accompanied by black or red edges where the fin is actually rotting away. I am not seeing this on Speck at all. His edges have always been white, and still are. I'll post a few pictures, and maybe you all can tell me what's going on. pH is normal, we've got a heater on him that keeps the temp where it needs to be, ammonia levels are safe and we've made sure his artificial plants aren't the culprits. The only other concern we have is that he might be having problems with the filter, although I think the current it generates is very minimal (but I suppose I'm not a fish either). We keep each of our bettas in a Mini-Bow 2.5 gallon, if that helps give an idea of the filter used.
Thanks in advance!