There is a tiny pin preick hole in Dorian's tail near the very end... It'a only really noticable when he flares up, I think he tore it when he was flaring up or when I was moving him to change his water (whoops :(). His fins are abnormally long (comapred to the other bettas I have seen) so they are very delicate.
I'm not overly worried about it (should I be) I just want to know what sort of product to look for when I go to the aquarium store later today to heal this little rip before it gets any bigger.