Scientists have captured rare 4K footage of a deep-sea fish with a transparent head and unusual green eyes in the Pacific Ocean. Known as the barreleye fish, the rarely spotted marine creature was filmed by researchers from the Monterey Bay Aquarium Research Institute (MBARI) during an expedition off the coast of Monterey, California.
The extraordinary sighting offers a closer look at one of the ocean's most unusual species and its remarkable adaptations to life in the deep sea.
Barreleye Fish Spotted Nearly 2,000 Feet Underwater
The six-inch-long fish was spotted on October 22, approximately 90 kilometres off Monterey Canyon, at a depth of around 1,970 feet. Researchers used a remotely operated vehicle (ROV) named Doc Ricketts to record the encounter.
The team, aboard the research vessel David Packard, observed the creature for nearly 20 minutes, capturing detailed footage of it hovering in the dark waters.
Scientifically known as Macropinna microstoma, the barreleye generally inhabits ocean depths between 2,000 and 2,600 feet. Its most distinctive feature is a transparent, dome-shaped head through which its bright green eyes are visible.
Why The Transparent Head Makes It Unique
The fish's unusual anatomy has fascinated scientists for years. Its tubular eyes can rotate within its transparent head, helping it look upwards for potential prey and forward when feeding.
Expedition senior scientist Steven Haddock said he had encountered the species several times, but his previous sighting was nine years ago, before MBARI introduced 4K cameras on its submersibles.
“It is such an amazing creature, which looks like it was created by an imaginative child,” Haddock said.
He added that earlier illustrations often failed to show the transparent dome because it was damaged during the collection of specimens.
“So to see it alive with the dome of its ‘cockpit’ intact is a real privilege,” he added.
Footage Could Help Scientists Study Deep-Sea Life
The newly captured visuals could help researchers understand how deep-sea creatures use vision in environments with little sunlight.
Haddock explained that these animals rely on subtle optical signals, such as shadows passing overhead, to survive in the ocean's midwater regions. The sighting offers another opportunity to explore their remarkable evolutionary adaptations.
