The aquarium has a water container (10) defined by a base plate (14) at a lower end, and comprising inlet openings (22) for feeding water in the water container, and a suction opening (24) for sucking water from the container. The inlet openings are connected with each other by a supply pipeline (18) e.g. ring line, and the suction opening connects a inner space of the container with a water space provided below the base plate. A discharge pipeline (20) is displaced in the water space and comprises a number of intake openings for intake of water.
