There is big variety of food out there so you can ask someone in store Somebody recommended hikari micro wafers to me and since I've been feeding those, my boys are very happy. They are small enough for them to comfortably eat and have high % of protein. You can switch them now and them with other food for variety if you like. Some bettas are really picky so it may take a while to get used to new food, but don't give up. Good luck.