He's most likely reconstructing his nest! how many days has it has it been since the spawning? once the eggs are put in the nest and 4 hours are passed remove the female, then the male guards and stays with the nest for 3 days. keep the male in for 3-4 days or until your fry are free swimming! U must remove when this is happening because his appetite that this time revives and will eat the fry. U also MUST NOT FEED HIM after the spawing proccess takes place. Male bettas Fast when caring for the eggs and nest. FEED HIM WILL RESULT IN OPENING UP HIS APPETITE AND EAT YOUR FRY! After the fry have hatch and are free swimming and its been 3 days after hatching you feed your fry
Hikari info : Hikari First Bites feed this for 6 days then u have to switch and mix up with live food, baby brine shrimp
San Francisco Bay Brand is what i use and the POWDER fry food. microworms are also used by breeders like myself. Anymore info and how-to's i'll be glad to help!