Abstract: A portable, universally adaptable water control device for use in conjunction with any conventional aquarium and for incorporation into the recirculation water filtration and aeration system thereof for automatically maintaining a predetermined level of water in an aquarium tank and for continually removing water solely from the top surface of the water contained in the aquarium tank and filtering and aerating the same when in operation; the water control device is adapted to be supported on a wall of the aquarium tank and includes an open-topped overflow receptacle positioned within the aquarium tank, an open-topped pre-filter receptacle positioned externally of the aquarium tank having its interior divided into a water-receiving compartment and a drainage compartment by a vertical partition wall, and a siphon tube for transferring water from the bottom of the overflow receptacle to the bottom of the water-receiving chamber; the siphon tube has both of its ends at the same level which level is below the leve