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 fresh or saltwater fish.