Perfect for vacation or long weekends, PondCare Fish Feeder Blocks ensure that fish receive adequate nutrition when pond keepers aren’t home to provide regular feedings, or when new or young fish can’t compete with established pond residents at feeding time. Turn tub over and lightly tap on solid surface to remove block. Drop block(s) in pond. They will dissolve slowly releasing nutritious pellets to automatically feed approximately 5 goldfish or koi (5-10 inches in length) while you are away. Gives great peace of mind while you are on vacation! Lasts 5 to 7 days.