animal Type
Maximum Size

15 cm

(6 inches)

Depth

600–800 m

(2,000–2,600 feet)

Habitat

Midwater

in the twilight (mesopelagic) zone

Diet

Zooplankton

including crustaceans and siphonophores

Range

North Pacific Ocean

Bering Sea to Japan and Baja California

About

These deep-dwelling fish can see through their own foreheads.

Even in a world full of adaptations for seeing in near-total darkness, the barreleye fish (Macropinna microstoma) stands out as one of the most bizarre. Two small indentations where eyes might normally appear on a fish are actually the barreleye’s olfactory organs, and its eyes are two glowing green orbs behind its face that gaze up towards the top of its head.

In 2009, MBARI researchers showed that the fish can rotate its eyes towards the front to see its food when eating. Before that, scientists believed that the barreleye’s gaze was fixed looking straight up. Researchers think that the fish hovers below a siphonophore’s tentacles to steal food.

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