Device for cage (1) for shellfish farming, where the cage is placed in the sea or in a tank with water and where the cage's one side (11) is provided with openings, for instance a grid (13) and where the cage's other sides (3, 5, 7, 9) preferably are closed and where the cage (1) is arranged so it can be turned so that the one side provided with openings (11) faces upwards in a vertical feeding position, or faces sideways in a horizontal eating and resting position, or faces downwards in a vertical emptying position, as these positions are achieved by means of the fish farming cage (1) being placed on or by a transporter (25, 55).