I have an idea of what to do with my 3 red bellies. I would throw in 20 feeder fish and once they were all gone I would feed them flake food for a day and then 20 more feeders that next day. Would it work or would I overfeed them?
they will only eat as much as they want.
the problem with overfeeding is not the fish getting too big, but the waste it produces in the tank.
If you keep the tank clean and remove the debris after they have finished eating there will be no problem.
also I find my piranhas are better with floating sticks and floating cichlid balls than flake food.