Abstract: A divider for fish aquariums, comprising a dividing wall that is specially designed for use in fish tanks to keep feeder fish and predatory fish in separate sections during non-feeding times, helping to better control the feeding habits of the latter is provided. Basically square in shape, the Control Feeder for Fish Tanks is offered in various sizes to accommodate virtually any aquarium. The present invention is made from durable, clear plexiglass material, and outlined with rubber sealant to keep the divider securely in place while in use. Outfitted with a series of small openings to facilitate water flow, the Control Feeder for Fish Tanks also contains three (3) larger, circular openings, which can be opened and closed via a sliding door mechanism to allow the feeder fish to pass into the predatory fish section of the aquarium.