Argyropelecus lychnus, the Tropical Hatchetfish, is found to depths of 700m (2100 feet). This mesopelagic species has photophores along the lower side of its body. The photophores produce a dim blue light. A predator looking upward from below might normally see a fish silhouetted by the dim light from the ocean's surface above; however, the blue light from the photophores matches the dim light from the ocean surface and conceals the hatchetfish. This cryptic use of bioluminescence is known as counterillumination. This specimen was trawled from 1000 feet depth off of Monterey, California, in November 2009.