"Macropinna microstoma is a deep-sea ray-finned fish in the barreleye family Opisthoproctidae.
The species was discovered and described in 1939 by the U.S. marine biologist Wilbert McLeod Chapman.
It occurs at lower mesopelagic depths beneath temperate and subarctic waters of the North Pacific from the Bering Sea to Japan and Baja California, Mexico.
Macropinna microstoma measures around 15 cm (6 inches) in length.
It has a tiny mouth, most of its body is covered with large scales, and its eyes are capped with bright green lenses.
It also has a highly unusual transparent, fluid-filled shield on its head. This protects its sensitive eyes from the nematocysts (stinging cells) of the siphonophores, one of the apparent sources of its food.
The barreleye lives in the ocean’s twilight zone, at depths of 600 to 800 m (2,000 to 2,600 feet." SciNews