Depends on the fish.
My fish & feeding schedule (all live in the same tank):
Badis badis - fed twice a week (once frozen bloodworms, once live blackworms)
Indostomus crocodilus - fed once a week (target fed vinegar eels) - They eat infusoria found in tank constantly
Boraras brigittae - fed twice a week (on different days as Badis badis and Indostomus crocodilus, as they will grab a few worms/eels for themselves) - Fed Captain Bob's "Sink or Swim" flakes or granules
Otocinclus affins, O. cocama, O. vittatus - fed three times a week (algae wafers twice, fresh veggies like zucchini, cucumber, sweet potato, kale, seaweed once) - They also eat algae in tank constantly
Carinotetraodon travancoricus - add snails if I don't see any for her to eat. She will also eat bloodworms and blackworms with the Badis badis if she feels like it (once or twice a month usually)