Aquarium Pharmaceuticals 144B Fish Feeder Block, 5 oz. Calcium blocks impregnated with specially formulated fish food pellets Provides continuous supply of nutritious food pellets for all pond fish if you're on vacation or between regular feedings Supplements diet if regular feeding is interrupted; Perfect for vacation or long weekends Ensures that new or young fish who can't compete with established pond residents get adequate nutrition Lasts 5-7 days