Food to feed a Betta fish

So I'm on my second betta fish Thai and things are a little different. When I first got him i fed him the topfin pellets and he ate them. When I moved him to his new home, he ate the top fin pellets for the first couple of days, but then after that he wouldn't eat them. So this was my thought, that you know how when a betta fish is trying to adapt to his new home, that they don't eat, but he would soon as he was more comfortable. I also had tried to feed him the Hikari Betta bio-gold pellets too, but all he did was just look at them and turn away. I actually had bought these freeze dried blood worms, which he absolutely loves, but what i'm worried about is if he's getting enough nutrients and if what I heard about supplementing pellets with the bloodworms is what I should do. But if he doesn't like the pellets what should I do? Also a little off topic but do all betta fish like to put their faces in the rocks, but not like they are scratching themselves on the rock?

When you change aquariums on any fish, it usually decreases their appetite. Bettas don't eat very much and, like most aquarium fish, they can go for several days without eating. Rather than focusing on the fish's appetite, you may want to make sure all the water parameters are correct. A healthy appetite usually follows a healthy environment. Please ask if you need more details.

But even if the water parameters weren't all that great why is he eating the dried bloodworms, but not the pellets?

Water parameters are the first thing to consider. Even if the Betta does not feel good, he may eat some of his favorite food just like you or I would if we were sick. Provide him with a good environment, and his appetite will emerge. An aquarium is an isolated, closed environment; the Betta or any other fish has to live where you put him/her. The objective then becomes to provide a healthy environment for a healthy fish. It's not all that difficult, but the procedures are sort of rigid.

any type opf tropical fish flake food works, in my 20 gallon i have 2 females and they eat the flake food like it was the betta bits