Floating door fish pen

An improved pen for holding captured aquatic creatures in submerged confinement is disclosed. A non-buoyant housing is provided with a plurality of small, flow-accommodating openings of sufficient size to allow water to pass therethrough, but small enough to effectively confine captured creatures of a desired size. The pen also includes a buoyant door that is adapted to open in response to the exertion of downward pressure thereon if such pressure is sufficient to overcome the upward buoyant force exerted on the door by the surrounding water. Supports are provided to accommodate ropes, chains, or other lift assist means.