Gday mate and

Best foods according to me:
Commercial: Hikari Lionhead & Sera Goldy Royal. Heard that Pro-gold is great also, but real hard to find here in Australia
Live: I never fed live food, but heard that tubifex worms are great and i'd really like to feed my fish brine shrimp if i got the chance.
Natural: Veggies like zucchini, duckweed, peas, and whole other things.
Algae that grows naturally in ur tank
Frozen bloodworm, frozen brine shrimp
hope that helps