Mechanical and biological filtration filter - Equipped with small scattering stones, filters and organic bead filter materials to add necessary oxygen to the water and ensure a quiet working environment 【This is an easy to disassemble filter】The first separator is a sponge for mechanical filtration, the second separator is a clay ball filter for biology, the last layer is the base which is connected to the air tube. Innovative ultra-thin design: save aquarium space, more beautiful, filter dimensions: 7.1cm x 8.1cm 【Its working principle is to connect the filter to the air pump through the air pipe and inject the air flow from the air pump into the filter. The vacuum air displaces the water flow through the sponge and clay ball to achieve the effect of water filtration and oxygen enrichment. 【Wide application】 No danger to fish, suitable for shrimp ponds, breeding ponds, goldfish, discus, guppies, young baby fish or other fish