Good for you for saving this guy! More than once, I've gone in to my petco and wished I could rescue at least one of their bettas, but alas, I live in a college dorm and already have too many fish... Glad the stupid Petco employees ("Oh, we'll send him back to the vendor, where he will surely die a miserable death... It's their fault for sending us a crappy fish!) finally caved!
I got him to eat some pellets today! I had to drop a TON in there for him to notice, and he only was interested in the floating ones. The only reason I put so much food in there was because I wanted him to see it as food, and I was about to give him a methylene blue bath and change his QT tank water.
There isn't much of a change, he might have a bit more color and he does have trouble swimming.. I'm glad he ate something because he really is very skinny.
He still rests at the top all day/night and I'm yet to see him swim very much. His fins haven't started healing yet either. I have been doing daily 100% changes with AQ salt, fish protector and prime. I hope he gets better!