The third food for betta fish that I recommend is "Pellet food" because it is comfortable and does not make sewage as quickly as fresh food.
But I don't advice to use pellet food for a long time because it don't have enough nutrients reached for betta fish.
You can easy find pellet food at the fish shop nearly your home. There are a lot of brand but I advice that you must buy pellet food which has protein at least 42%. Your betta will quickly grow and healthy with this 42% protein or more.