some carnivorous fish need only to be fed a few times a week whe they are adults, but when they are still growing (which most captive fish are for several years) they need to be fed daily, with the possiblity of one day a week fast.
when they are adults you only want to feed a few times a week, because when they are full grown the concentrated protein can become damaging, where when they are growing they use alot more of that protein. jsut like puppies into dogs.