Time Release food Block made especially for sucker-mouth type Catfish. Contains algae and wood fiber necessary for the long term health of your Catfish. Time release food block is great as a vacation feeder. Great supplemental food source for difficult feeders. Provides opportunity for bottom feeders to wear mouthparts naturally. Additional Information:Place one Pleco Banquest Block per 2-3 small catfish or one medium to large size catfish being fed. Add multiple Pleco Blocks if you notice aggression during feeding time. Can be used for both fresh or saltwater fish.