New deep-sea sighting: The barreleye fish has a transparent head and tubular eyes

I spy with my barreleye, a new Fresh from the Deep! 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 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. Aquarist Tommy Knowles and his team were aboard MBARI’s R/V Rachel Carson with our ROV Ventana to collect jellies and comb jellies fo