Method for supply of oxygen and circulation of water in a fish farm (10), said fish farm (10) comprises a float collar (12) with a net (14), where the net (14) is closed at the upper area by a lice skirt (16) that extends partially down along the net (14), where the method comprises the steps: supply of compressed air at a lower part of the net (14), formation of an ascending water stream of air bubbles (30) and water in the net (14) and water that is sucked into the net (14) from surrounding sea, and where the water is sucked into the net (14) from the surrounding sea in a flow through area below the lice skirt (16). The supply of compressed air at the lower part of the net (14) is carried out in an area in the vicinity of the bottom ring (22) and remote from the centre of the net (14), and discharge of water to the surrounding sea is made in an area above the lice skirt (16), where the water is let out to the surrounding sea through a slit (20) between the lice skirt (16) and the float collar (12).
