Abstract: An aquarium cleaning system comprises undergravel cleaning apparatus and a fish tank having a bottom wall and side and end walls. The cleaning apparatus in the example illustrated comprises a rectangular frame having side and end walls sized to fit within the bottom portion of the tank. An apertured gravel-supporting floor plate is mounted on the top of the frame and defines a space within the frame beneath the plate. A stationary guide tube extends upwardly from the frame above the floor plate. A movable suction head is located within the space and is connected to a movable siphon tube extending upwardly through the guide tube. An upstanding aeration tube is mounted on the floor plate and has a coaxial air supply tube which supports an apertured wiper disc and an apertured filter cartridge, both having wiper elements engaged with the inside wall of the aeration tube to remove algae and detritus. The floor plate comprises two grid sections with parallel slits.