VIDEO: For the first time, a large Pacific barreleye fish – complete with transparent head – has been caught on film by scientists using remotely operated vehicles at the Monterey Bay Aquarium Research Institute. The deep-sea fish’s tubular eyes pivot under a clear dome.
Barreleyes fish, also known as spook fish, are named for their barrel-shaped, tubular eyes which are generally directed upwards to detect the silhouettes of available prey. The eyes protrude from the skull, and are visible under a soft, transparent dome that makes up the forehead and top, front of the fish’s head. The fish are capable of directing their eyes forward as well. Marks at the front of the fish that look like eyes are actually olfactory sensors.
The fish are found in tropical-to-temperate waters at moderate depths (from the mesopelagic to bathypelagic zone, about 1300–8200 feet down) in the Atlantic, Pacific, and Indian Oceans. The family contains thirteen species in six genera.