I also forgot to add that you only need to feed him the amount of food that could fit into his eye at each feeding. This is because that's about the size of their stomach. All of my Bettas would eat a lot more than that if allowed, but overfeeding can lead to health problems, like Swim Bladder Disorder, bloating and problems with water quality that can cause other illnesses. If he seems hungry after eating the right amount of food, he's ok. He will not starve to death or anything like that, he may just be a little piggy...^_^
Also, what fleetfish said.