Fish biomass (Tilapia sp.) were raised at high stocking density in 1‐m3 tanks containing 450 L of water. The water was changed continously by means of a jet flow regulator. The jet flow regulator maintained adequate dissolved oxygen (DO) and a low ammonia level, while the suspended solids were discarded. In such a system, an annual yield of above 15 kg/m3 can be expected. The application of the jet flow regulator in aquaculture is discussed.