The present invention relates to a netpen for breeding, storage, or transport of fish in the sea, in particular completely or in part in open sea regions outside the skerries, wherein the netpen may be lowered in the sea to a desired depth when needed, wherein the netpen may be elevated to a half or approximately half submerged state for various work operations, such as maintenance and inspection of the netpen or harvesting, and wherein netpen has a substantially spherical geometry. The invention is characterized in that the netpen consists of a framework of stays (1, 2, 3, 4) mainly comprising polyethylene or polyethylene-like materials, such as PolyEthylene Low Density (PELD) or PolyEthylene High Density (PEHD), preferably PEHD, a horizontal through center pole (5) also serving as a buoyancy adjusting element for elevation and lowering of the netpen, a horseshoe-shaped working platform (6) having an integrated dock (7) for working vessels, the entire working platform including dock being liftable and lowerable through buoyancy adjustment by means of a designated element (13), and the working deck being mounted on an extended axle (15) on the center pole in such a manner that the netpen may be rotated inside said working deck. On said axle, through lines (8), there are also attached buoys (10) that gives the netpen sufficient reserve buoyancy in normal position as well as weighting organs (9) that, when the netpen is to be stabilized fully submerged at a desired depth, is landed on the sea floor; alternatively, the netpen is stabilized at the desired depth due to the reserve buoyancy in the floatation unit (30) and the floatation element (23), as shown in FIG. 30. Life-supporting functions, such as fodder, energy, and air, are being supplied to the netpen through a lifeline from a nearby floatation unit (30), preferably a platform being an integrated part of the anchoring for the netpen.