Feature: 

1. Sponge filters provide both mechanical and biofiltration, also, the air infusion chamber produces minute bubbles which increase the oxygen solubility
2. Safe for fish: soft sponge material, traps floating debris, and won't suck up your fish
3. Easy to set up & clean: simply install an airline into the unit and turn on the air pump, simply rinse and squeeze the sponge in the tank water
4. Excellent for small-size fish like betta, dwarf cichlid, guppy, killifish, etc., or for hatcheries, maternity tanks, nano tanks, and fry tanks, as the filter produces minimal current and has almost no way to suck the fish through the filter