Traps Floating Debris And Your Baby Fish From Being Sucked Up Into The Filter,Aerobic Colonize The Sponge Providing A Bacterial Substance To Facilitate The . Aquarium Sponge Has Two Media Containers With Ceramic Filter Media Inside Of Each,Will Help To Remove Harmful Substance And Increase Oxygen Level In Your Tank,You Can Replace The Filter Media To Enhance Water . Scientific 5-Layer Ribbing Shape Sponges Design,It Quickly Established A -Filter And Extra Oxygen,Two Sponges Means More Surface Area For Beneficial Bacterial To Colonize And Cycling,Keep Your Fish Tank And Clean. Easy To Install:Simply Install An Airline Into The Unit And Turn On The Air Pump,Great To Clean And Oxygenate Your Tanks;Easy To Clean. Aquarium Sponge Comes With 2 Suction Cups,Can Be Installed Anywhere And Can Be Easily On The Back Wall Of The Aquarium;Suitable For Shrimp Tank, Tank,Breeder Tanks,Goldfish,Discus,Guppies,Fry,Baby Fish Or Other Fish. Color:blue+green material:plastic Size about:19*7.5cm Specifications:Xy-2881 Contents: 1*Fish tank filter Only the above content, other are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.