Capture the rare sight of a transparent head fish swimming at a depth of 800m

The remote-controlled vehicle captured a rare sight of the barreleye fish, an animal with blue eyes that can peer through the forehead in search of prey.

The Monterey Bay Aquarium Research Institute (MBARI), released a new video of a strange fish with glowing green eyes and a transparent head on December 9. This is actually the barreleye (Macropinna microstoma), which was captured by a remote control vehicle during an expedition by the research vessel Rachel Carson in Monterey Bay, off the coast of California.

Barrelfish can see through their foreheads to see above and find prey. Scientists need to use remote control vehicles to record images because they often live at depths of up to 600-800 meters, far beyond human ability.

Barrelfish can see through their foreheads to see above and find prey.

The sight of barreleye fish is very rare. "Ventana and Doc Ricketts, MBARI's remote-controlled vehicles, have done more than 5,600 dives and recorded more than 27,600 hours, but we've only seen this fish nine times," MBARI said.

Barrelfish are used to working in the dark and their unusual eyes help them find food in such conditions. Experts at MBARI discovered they eat jellyfish and have a maximum length of 15cm. The two small depressions on their faces are actually olfactory organs, which can be considered as nostrils.

Initially, scientists thought that the eyes of barreleye fish could only see above the head, but a study published in 2009 showed that their eyes can rotate inside the transparent diaphragm so they can also see ahead. That helps the deep-sea creature keep an eye on what's getting into its tiny mouth.