Barreleye fish are named for their unique, barrel-shaped eyes. These eyes can rotate, allowing the fish to look both upward and straight ahead. Their eyes also have bright green lenses protected behind a transparent forehead, which gives the fish a futuristic appearance, almost like a sci-fi submarine.

Barreleye fish grow to about 6 inches long and are found in the northeastern Pacific Ocean, living at depths of 2,000 to 2,600 feet below the surface. The yellow pigment in their eyes helps them distinguish between the faint bioluminescent light produced by living organisms and sunlight. This makes it easier to spot the siphonophores and zooplankton that they eat.