It is described a floatable structure (1) comprising a cage (10) with a surrounding wall (11) and a bottom (12), the cage (10) being arranged for fish farming, wherein a surrounding skirt (21) extends in a downward direction from the bottom (12), wherein at least a portion of the bottom from the skirt towards a centre of the cage is tight, said portion of the bottom (12) and the skirt (21) forming a bottom section (20) arranged to be filled with a gas giving the floatable structure (1) additional buoyancy.
