Looks like my male silver molly has a case of swim bladder (or what else

).
If he tries, he can usually get himself swimming normally, but as soon as he relaxes, his tail goes right and and he ends up facing the bottom of the tank.
I've got him in a small "hospital" tank and haven't fed him in about 36 hours. Also added some Melafix and Pimafix as well.
I know he's not happy in this condition, but looks normal otherwise.
Is there anything else it could be? Is there something specific that I should be doing?
He was in my 33 gallon tank with about a dozen other fish, including another molly, and those fish are fine. They were getting flakes, dried bloodworms, algae pellets and some zuccini.