A system for efficiently circulating water in a large volume of rearing space for aquatic organisms, comprising an impervious enclosure for containing the water and aquatic organisms and a pump for pumping water from an intake duct through intake ducting to a flow diverter, which then directs a flow of water radially outward within the enclosure to directly induce a circulation of water within the enclosure. The &lsquocenter drive&rsquo circulation pattern is sufficiently uniform to provide optimum rearing conditions for cultured finfish, while also ensuring that solid wastes are swept toward the central drain, even in a very large tank.
