Depressed Betta?

Question
I adopted a sick betta fish that was living in poor water conditions in a  10 gallon, and have since moved him 6 days ago to a bigger 26 gallon tank with clean treated water [i test it daily for PH, ammonia, nitrates]
The PH is still running a little high at around 7.6 - 7.8 even though i had tried to lower it before I got him in there!
Well he was up the top swimming around for the first day then ever since he has been hiding under and around the driftwood, silk plants and hidey hole of a rock I got for him. I treated the water and had the tank running for only a week as I wanted to get him out of the bad water he was in and he has a TERRIBLE case of fin rot to boot. Anyways, he wont eat at all poor guy. I was wondering what else I can possibly do for him? He lives with one other fish I also rescued [a platie] and from what I can tell they seem to live in harmony for the past 5 months.
He seems so depressed, or could he be just hiding and making sure no predators are going to get him i this new BIG tank? Thanx for your time. Hoping to read your reply soon.  

Answer
He could be hiding but I doubt it. Does he still have fin rot or is all that cured? If it is, put him in a smaller tank with good water quality and keep the temperature up around 84F for him. If that helps keep him there until he acting like his oldself.
The no eating could simply be that he doesn't like the food (unless it's the original food), either way I would try giving him some bloodworms and see if he'll eat that.