Aquarium Pharmaceuticals 7-Day Pyramid Fish Feeder (0.7 oz.; 7 Day Feeder For Fresh & Saltwater)

One pyramid feeds 15 to 20 average sized fish in a ten gallon aquarium for seven to eight days. As the Pyramid dissolves, it releases pelleted fish food. There's even a mid-week feast! A treat of tubifex worms is released on or about the fourth day.