Fish farm construction (10) for the farming of marine organisms (30) comprising a float collar (12) equipped with an inner fish farm wall (14) that houses the marine organisms, and also an externally lying outer fish farm wall (16). The inner and the outer fish farm walls (14, 16) are each equipped with a number of openings (14a, 16a), in which respective openings (14a, 16a) overlap each other to permit through- flow of water in the fish farm or where respective openings (14a, 16a) are offset in relation to each other to close for through-flow of water in the fish farm, wherein the fish farm construction comprises means for causing mutual displacement of the inner and the outer fish farm walls, (14,16) relative to each other.
