People have suggested that you don't feed bettas flake food; it will cause bloating.
I've seen some suggest Hikari betta pellets, although I don't have them myself.
Because my bettas are in a community tank, I feed them the same food my other fish eat. I have a bunch of freeze-dried foods (brine shrimp, mysis shrimp, bloodworms, tubifex worms) that I soak first, then put in the tank. I used to just feed them the freeze-dried food without soaking them, but I think they bloated the bettas like flake food does, so I took someone's suggestion on these boards to soak freeze-dried food first.
Soaking them also helps them sink for my five banded barbs, who stay in the lower regions of my tank.
