KollerCraft TOM Rapids Mini Canister Filter, 80 GPH Hang-on-the-tank filter ideal for nano, mini-reef, and other small aquariums (up to 20 gallons) Purifies aquarium's water while extracting unwanted fish waste and other debris Self-priming, top mounted motor that delivers optimum flow rate (80 GPH) Integrated spray bar creates an even distribution of water Three-stage filtration (mechanical, chemical, and biological)