An aquarium gravel cleaning system 100 comprising a tubular member 4 comprising one or more openings 2 arranged along its length. The tubular member is connectable to a pump 17 arranged to suck water from within the tubular member. A receiving portion 3 arrangeable adjacent to gravel within an aquarium, comprises a passage 3a for receiving the tubular member. Said receiving portion comprises one or more openings 1 arranged along its length. The tubular member fits within the passage and is free to rotate with respect to the receiving portion. A drive member 21 is provided to rotate the tubular member with respect to the receiving portion. The openings of the tubular member and receiving portion are arranged such that there is an at least partial overlap between the openings at a particular longitudinal location and at a particular relative rotational position between the tubular member and receiving portion. As the tubular member rotates with respect to the receiving portion the opening overlap moves along the length of the tubular member and receiving portion and water from the aquarium is sucked into the tubular member from around the gravel at successive longitudinal locations.
