An aquaculture system for farming aquatic organisms, said aquaculture system comprising: an enclosure for oxygenated water in which aquatic organisms are to be farmed, wherein the enclosure comprises an inlet for feeding oxygenated water into the enclosure; an apparatus for supplying oxygenated water into the enclosure, the apparatus comprising: a water inlet for supplying water into the apparatus; an oxygen inlet for supplying oxygen into the water within the apparatus to create a water and oxygen mixture, wherein the mixture is free from colloidal minerals, the oxygen inlet being in fluid communication with, and downstream of, the water inlet; a mixing chamber in fluid communication with, and downstream of, the water inlet and the oxygen inlet, the mixing chamber comprising one or more obstacles and/or a tortuous path to induce turbulence into the water flowing therethrough and break-up the oxygen into a plurality of oxygen bubbles; a venturi in fluid communication with, and downstream of, the mixing chamber, such that the water and oxygen mixture is supplied to the venturi, wherein the venturi is arranged to dissolve the oxygen into the water passing through the venturi without application of an external magnetic field; and an outlet for the oxygenated water in fluid communication with, and downstream of, the venturi; wherein the outlet of the apparatus is in fluid communication with the inlet of the enclosure; and wherein the apparatus is arranged to produce oxygenated water with a concentration of dissolved oxygen of between 62 mg/l and 125 mg/l, e.g. between 80 mg/l and 100 mg/l. an enclosure for oxygenated water in which aquatic organisms are to be farmed, wherein the enclosure comprises an inlet for feeding oxygenated water into the enclosure; an apparatus for supplying oxygenated water into the enclosure, the apparatus comprising: a water inlet for supplying water into the apparatus; an oxygen inlet for supplying oxygen into the water within the apparatus to create a water and oxygen mixture, wherein the mixture is free from colloidal minerals, the oxygen inlet being in fluid communication with, and downstream of, the water inlet; a mixing chamber in fluid communication with, and downstream of, the water inlet and the oxygen inlet, the mixing chamber comprising one or more obstacles and/or a tortuous path to induce turbulence into the water flowing therethrough and break-up the oxygen into a plurality of oxygen bubbles; a venturi in fluid communication with, and downstream of, the mixing chamber, such that the water and oxygen mixture is supplied to the venturi, wherein the venturi is arranged to dissolve the oxygen into the water passing through the venturi without application of an external magnetic field; and an outlet for the oxygenated water in fluid communication with, and downstream of, the venturi; a water inlet for supplying water into the apparatus; an oxygen inlet for supplying oxygen into the water within the apparatus to create a water and oxygen mixture, wherein the mixture is free from colloidal minerals, the oxygen inlet being in fluid communication with, and downstream of, the water inlet; a mixing chamber in fluid communication with, and downstream of, the water inlet and the oxygen inlet, the mixing chamber comprising one or more obstacles and/or a tortuous path to induce turbulence into the water flowing therethrough and break-up the oxygen into a plurality of oxygen bubbles; a venturi in fluid communication with, and downstream of, the mixing chamber, such that the water and oxygen mixture is supplied to the venturi, wherein the venturi is arranged to dissolve the oxygen into the water passing through the venturi without application of an external magnetic field; and an outlet for the oxygenated water in fluid communication with, and downstream of, the venturi; wherein the outlet of the apparatus is in fluid communication with the inlet of the enclosure; and wherein the apparatus is arranged to produce oxygenated water with a concentration of dissolved oxygen of between 62 mg/l and 125 mg/l, e.g. between 80 mg/l and 100 mg/l.