usually once a day somtimes in the afternoon when he is active. I've tried previously to feed him twice a day but he could care less about food and more about swiming.
On weekdays I usually feed all my fish when I get home from work or my fiance will feed them when he gets home from work. On weekends (mainly only on Sundays) though, it's fair game and they get to eat a meal in the morning of bloodworms or brineshrimp and then a mini snack if I'm home of hikari micropellets (I don't know why the bettas love those also) and daphnia and then they get regular food (pellets and flakes) in the evening... The routine's worked well since day one.