Pacific’s Mysterious Barreleye Fish: A see-through glass-headed creature with glowing eyes to spot prey

Pacific Barreleye Fish: The Strange Creature with a Glass Head (Image: Canva)

Imagine seeing out of your forehead. That is what the Pacific barreleye fish can do. This rare deep-sea fish lives in the North Pacific Ocean. Its transparent head and rotating eyes make it stand out.

Experts say it resembles an alien creature. Researchers at the Monterey Bay Aquarium Research Institute (MBARI) examined it extensively. They found out how the fish endures in extreme depth.

Why is the Barreleye Fish Different?

Why does the barreleye possess a transparent head? Scientists explain the transparent shield protects its sensitive eyes. This tough layer covers the fish’s tubular eyes. The eyes glow green to detect bioluminescent prey. The barreleye’s eyes can rotate upwards and forwards. They can move in a 75-degree arc. The green pigments in its lenses filter sunlight. This helps the fish spot faint light signals.

The transparent shield also contains a fluid chamber. It offers extra protection from stinging tentacles. These features help the fish survive deep waters. It lives between 660 and 3,300 feet below the surface. Most often, it is found between 2,000 and 2,600 feet. The barreleye’s body is greyish-brown with flat fins. These allow it to hover almost motionless. Its size reaches about six inches in length.

How Does the Barreleye Fish Hunt Prey?

What does the barreleye fish eat in darkness? It feeds on zooplankton, both gelatinous and crustacean. Scientists also believe it steals prey from siphonophores. Siphonophores are long invertebrates related to jellyfish. Stomach analysis showed the presence of siphonophore tentacles.

How does it avoid injury while stealing prey? The fish hovers beneath the tentacles with precision. It looks upward to spot prey in light. The transparent skull protects eyes from stings. Once it spots food, the eyes rotate forward. The fish then swims upward to capture it. This clever method helps it gather meals safely. Researchers say the barreleye is a stealthy predator.

How Do Modern Tools Reveal the Barreleye’s Secrets?

Why is the barreleye so rarely seen? Despite more than 5,600 MBARI dives, only nine sightings exist. Underwater robots help scientists observe the fish closely. High-definition cameras capture its behaviour in detail. These technologies revealed how the fish moves and feeds.

The barreleye’s ability to navigate among jellyfish is remarkable. It carefully picks off trapped prey without harm. Experts continue to study its life cycle. Its role in the ecosystem remains a mystery. The barreleye fish shows how life adapts deeply. This rare creature continues to fascinate marine researchers worldwide.