Abstract: A method for keeping fish in a live and healthy condition, wherein the fish are placed in an endless flow fish tank, which occupies relatively little space, yet allows instinctively swimming fish to swim comfortably. Aerated water is pumped in one direction through a swim chamber, and water returns through a space between inner and outer container, through return flow piping, or through a second swim chamber which also serves as a return flow chamber.

Abstract: A high efficiency impeller-type aerator designed for aeration of the water supply of aquatic organisms has a first impeller, a second impeller, and a pump casing having at least one water inlet, one air inlet, and one water outlet. The first and second impellers are disposed between the pump water inlet and outlet, and the pump casing includes constricted portions in association with the first and second impeller to define axial flow direction boundaries. The air inlet is located at the constricted portion, and the axial flow direction boundaries define a channel through which the second impeller urge water to facilitate low pressure that creates a venturi which causes air suction at the pump air inlet.

Abstract: A high efficiency impeller-type aerator designed for aeration of the water supply of aquatic organisms. The aerator design includes a first impeller (booster), a second impeller (main impeller), and a pump casing having at least one water inlet, one air inlet, and one water outlet. The first and second impellers are disposed between the pump casing water inlet and outlet. The air inlet is positioned advantageously between the first impeller and the second impeller and is in communication with air, and wherein the water inlet and outlet are in communication with water. The efficiency of the pump is retained while the bubbles produced in accordance with the present invention are advantageously small.