Wardley Shell-shaped feeder automatically dispenses food while you're away for the weekend Feeds a 10 gallon tank of freshwater tropical or goldfish for up to 3 days Slowly dissolving food stabilizes pH levels during feeding Contains no artificial colors or dyes that can harm fish or cloud water Place the shell into your tank prior to leaving for the weekend. It will slowly dissolve, releasing small food particles One shell feeds 10-12 average sized fish in a 10-15 gallon aquarium