The Penn Plax PBV1 7-Day Vacation Fish Feeder is a great way to feed your fish while you’re on the go. This feeder features time-release blocks that can be used in your aquarium for up to 7 days. Made with pro-quality fish food, it contains fish favorites like tubifex and bloodworm along with essential vitamins and minerals. Place one of these in your aquarium, and the block will slowly dissolve releasing the nutritious freeze-dried foods.