BRAND NEW Sponge filter provides both mechanical and biological filtration. Simply install an airline into the unit and provide both aeration and filtration for your fish. In addition, the 4 1/2 inch sponge filter traps waste particles.Easy-to use biological filter for tropical aquarium fish Aquarium filter sponge for efficient biological filtration Great biological filter for breeding or spawning aquariums Produced from high quality hydrophilic filter material. Multi-strata design provides large surface area for optimum filtration. Provides the ideal location for bacterial colonization. Operated by an air pump to create numerous minute bubbles to increase dissolved oxygen content. Replaceable filter sponge allow long lasting use. Does not trap fish fry. Suitable filter when breeding and spawning Discus, Dwarf cichlids, guppies, and killifish. These filters allow you to cultivate nitrifying bacteria for superb biological filtration. Great for fry aquariums and brine shrimp hatcheries because they prevent young fry from being trapped in the filter media. Operates silently, creating numerous minute bubbles for increased oxygen flow. Maintenance Rinse the sponge with cool or warm running water weekly. Do NOT use hot or very cold water as this will destroy the bacteria which colonize the sponge.