I just noticed that when I feed my Betta his little bits... he will take it into his mouth like normal, and then spit it out and it will sink to the bottom of the bowl. I tried to feed him a smaller piece, and he did the same thing. I don't know what to do. Please help!

I'm not a betta expert, so I'm not SURE about this, but it sounds to me like:

a) He isn't really hungry
b) He doesn't like the food you are feeding him
c) A combination of both

I've seen a lot of fish do this mouthing/spitting behaviour over the years (mostly goldfish). With goldfish they do it a lot with poop. It's like a 'hey, this looks like food-- ewwwww' reaction. This is what leads me to think that he's not a fan of the food. You could try switching to another kind and see if the behaviour stops-- there are a ton of options out there. Alternately, try feeding him a little less than normal. It's a frequent problem that people overfeed their fish. They have tiny little tummies, so they don't really need as much as a lot of people think. Also, I know a beta breeder who says it's not a bad thing to NOT feed a beta for a day. This helps clean out their system, raise their activity level, and increase their appetite for the rest of the week.

Just some thoughts.

How long have you had him? It's not uncommon for bettas to refuse food if they have only been fed something else before you got him. (Which, if you got him at a petstore, you don't know what they were feeding him) Also, if you just got him, sometimes they're stressed from the moving process and will not eat. Just keep trying; he'll eat when he's hungry enough. They can go a long while without eating. Try feeding him some other types of food for variety - frozen bloodworms or brine shrimp are good options to try.

Your pellets may be too big. The hikari betta bio gold are good as well as Atisons Betta Pro. The rest of the brands I have found to be too big, and my betta will spit them out b/c he cant swallow it.