[Improve water quality] The sponge filter has a large porous surface where aerobic bacteria can multiply. The growth of nitrification bacteria can provide excellent biological filtration for your tank. Bettas, fry and other small fish are never sucked into the filter. The low flow rate of this filter is ideal for breeding and spawning discus fish, dwarf cichlids, guppies and dead fish. [Fine filtration] The sponge traps dirt in your tank as water passes through the pores, making the water crystal clear. It is very effective and breaks down toxic waste in the tank. Easy to clean and reuse: the sponge can be used multiple times. When changing water, do not use tap water, but use tank water for cleaning. Rinse and wring it out several times until the water runs out of the sponge. Versatility: This aquarium filter is small and can be easily hidden behind plants. Fits in any corner, perfect for shrimp aquariums, breeding aquariums, betta aquariums, nano aquariums, fish aquariums, turtle aquariums, goldfish, larvae or other fish.