The fish culturing system includes a culture tank for raising fish, a multi-stage filter system to clean the water in the culture tank, and an air manifold supplying air to the whole system. A water return manifold substantially surrounds the upper portion of the culture tank and a waste output manifold substantially surrounds the lower portion of the culture tank. Water flowing through the water return manifold exits through a plurality of openings into the culture tank and an air diffuser assembly aerates and induces opposing flows in the water in the culture tank. Waste material in the culture tank is drawn through the waste output manifold and directed through the multi-stage filter system to remove solid waste and reduce toxic levels of ammonia. At least one clean-out port communicates with the water return manifold and the waste output manifold for respective cleaning. An adjustable overflow pipe regulates water levels.
