A diffuser hose for oxygenation of water, in aquaculture installations for marine organisms in the sea. The hose (5) consists of a perforated hose (6), to which substantially pure oxygen is supplied, and at least one perforated hose for oxygen distribution (7), wherein the supply hose has fewer perforations/holes/pores than the distribution hose, thereby providing pressure equalization. Diffuser hoses herein provide for the formation of oxygen microbubbles with an oxygen partial pressure that is such that the oxygen passes into the water in the fish farm.