Bizarre Fish that Sees through its Transparent Head

Divers during a dive came across a rare treat: a barreleye fish that sees through its transparent head.

During a dive with our education and outreach partner, the Monterey Bay Aquarium, the team came across a rare treat: a barreleye fish (Macropinna microstoma).

MBARI’s remotely operated vehicles Ventana and Doc Ricketts have logged more than 5,600 successful dives and recorded more than 27,600 hours of video—yet we’ve only encountered this fish nine times!

The barreleye lives in the ocean’s twilight zone, at depths of 600 to 800 meters (2,000 to 2,600 feet). Its eyes look upwards to spot its favorite prey—usually small crustaceans trapped in the tentacles of siphonophores—from the shadows they cast in the faint shimmer of sunlight from above. But how does this fish eat when its eyes point upward and its mouth points forward? MBARI researchers learned the barreleye can rotate its eyes beneath that dome of transparent tissue.

[MBARI (Monterey Bay Aquarium Research Institute)]