I honestly don't really see any fin rot..
Fin rot won't cause a change to the fish (other than blackened edges that seem to be flaking off) or show illness signs until the rot has eaten all of the fins and is attacking the body. But I don't see any rot..
What were his symptoms before you took him out?
lexy is correct, remove him from Melafix right away and just into a tank with water conditioner and (ONLY IF he is gasping for air) 2tsp of AQ salt per gallon and then you will be doing daily 100% water changes with the AQ salt/conditioner for no longer then 10 days (or sooner if he recovers).. the AQ may be able to help any gill troubles he got from Melafix.. also if he does have any form of rot, the AQ salt will kill it.
If he isn't gasping, then keep him in his hospital tank, keep the temp up around 78-80, water conditioner only in his tank and keep an eye on him over the next day or two.
Let us know any symptoms he had that made you pull him out of his home so we can find out what is really going on with him.
Last edited by Myates; 11-20-2012 at 07:38 PM.