Baby Channel Catfish. Each pond supports a limited number of catfish per acre, so channel catfish commonly becomes overpopulated without bass. I keep the pond stocked with bluegill to serve as feeder fish for the catfish.
I keep 100+ of them in a one acre pond that tapers from a depth of two feet to a depth of 12 feet. Place some java moss or similar bedding plants into the tank. A power filter could suck the tiny fry into the water intake tube.