The large Pleco Feeder is 15 1/2 inches long and will work well in 15 and 20 gallon tall tanks andtanks that are 30 gallons and larger. It is made from 316 Stainless Steel and food grade silicone rubber and will provide a lifetime of service. It makes feeding your plecos and other aquarium fish a varied healthy diet quick and easy. Just screw a piece of fresh shrimp, zucchini or any vegetable and place it in your tank. A healthy fish is a happy fish. Your plecos and other fish will eat this new fresh food and soon learn when you place The Pleco Feeder in the tank that they will get a tasty treat. Great for fresh or saltwater fish.