beta fish with missing fin

Question
I just noticed that our beta fish is missing the dorsal fin and there is a nasty wound where it used to be.  He has always been in the bowl alone and there is nothing sharp in his home.  Is it abnormal for this to happen naturally?  Will he live and is he in pain?

Answer
Hi Marcia,
 His fin is gone but he is alone?  That is very unusual.  Fins do grow back but it is very curious that it should have gone away.  Have you been doing regular water changes?

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>