I dont see the purpose of taking predatory fish of feeders. My GCK is 24 inches, eats feeder fish once a week and what ever algae pellets he manages to steal from the other fish. I believe it will keep his hunting insticts in tack. I spend 3 dollars a week on goldfish. He eats 12 in a day. Been doing that for two years now and he is very healthy. He will stop the other fish from feeding on the pellets if he is hungry enough.