Abstract: A special, single-piece, absorbent sponge acts as the main filtering element for an aquarium filter. The present invention incorporates conventional air lines, bubble tubes and stem sockets in a unique arrangement in combination with a novel filter in the form of a contoured sponge. The surface of the sponge filter is contoured which creates large total surface area for facilitated absorption of dirt. Under magnification, the sponge filter is composed of thousands of tiny plastic rods joined together which exponentially increase total surface area. The tiny plastic rods within the expansive surface area create hundreds of thousands of "corners" which encourage habitation of microscopic protozoa. The present invention is designed for a multitude of applications including: filtration of waste products, creation of a balanced ecosystem essential for successful aquariums, establishment of filter beds, and utilization as hatcheries for brine shrimp and fry.