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Barreleye Fish
Macropinna microstoma
Least Concern
Location
North Pacific Ocean (600-800m depth)
Size
15 cm (6 inches)
Diet
Carnivore
Habitat
Deep ocean twilight zone
About This Animal
The barreleye fish has a completely transparent head filled with fluid, allowing its tubular eyes to rotate upward to spot prey silhouetted against the faint light from above. This bizarre adaptation makes it one of the most alien-looking creatures on our planet.
Amazing Facts
Has a completely transparent, fluid-filled head
Eyes can rotate 90 degrees to look straight up through its skull
Was first described in 1939 but transparent head wasn't discovered until 2004
Steals food from siphonophores using its precise eye movement
Can remain motionless for hours waiting for prey