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 is provided. The netpen may be lowered in the sea to a desired depth. 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. The netpen has a substantially spherical geometry. The netpen consists of a framework of stays, a horizontal through center pole also serving as a buoyancy adjusting element for elevation and lowering of the netpen, a horseshoe-shaped working platform having an integrated dock for working vessels. The entire working platform including dock is liftable and lowerable through buoyancy adjustment using a designated element. The working deck is mounted on an extended axle on the center pole. The netpen may be rotated inside said working deck.