A simple tank system, using artificial aeration to supply oxygen and incoming water to dilute metabolic by-products and other wastes, was tested. Blue tilapia, Oreochromis aureus, were grown under a wide range of loads, 7-31 kg liter -1 min -1, and densities, 19-77 kg fish m-3 culture unit. Average yield ranged from 6-10 kg m-3 culture unit per month. Approximately 14-20 m3 of water was used for each kilogram of fish produced.