I am not an expert, but I have done a little bit of research. First off, what type of food are you feeding your betta? Are you feeding him flake food, pellets, etc... Some bettas refuse to eat some types of food. My betta for example will gobble up his pellets, but will spit out any flake food I give him. My betta LOVES his pellets, while he for some reason won't eat any other food (blood worms, etc...)
Also, he might be a little stressed still. I would give him a day or two to get used to his environment. Bettas won't die if they go awhile without food. He can go a few days and be OK.
I want to remind you to make sure his tank is a warm temperature because when my betta stopped eating, it was because he was cold. Also, does it seem like he has some disease like ich, or fin rot? Those can make him not want to eat if they are too bad.
Remember, I am not an expert (I am far from an expert...), but I hope this helps a little. If someone else posts, they are probably more experienced than me, and know more. I am somewhat sure he will be OK though. It doesn't sound like he has anything bad going on with him, and if he is healthy looking, chances are, he is healthy.