Fine Sponge Filtration: It provides mechanical and biological filtration and traps debris or waste without sucking up your fish, helping to maintain a crystal clear tank water. Easy to Clean: The filter can be easily detached to clean dirt. Rinse it every 2 to 4 weeks with aquarium water ONLY. Avoid washing it with tap water! Quiet Aeration: Works with air and does not disturb your daily life. Squeeze the sponge in the tank to completely absorb the water in the tank and make it flow to the bottom. Air pump not included: You need an additional air pump to operate the filter, which processes outside air to promote oxygen circulation, providing a healthier environment for the aquarium.