Splitfin or Giant Flashlight Fish (Anomalops katoptron).

Flashlight fish are in the family Anomalopidae. The Splitfin or Giant Flashlight Fish, Anomalops katoptron, is the largest of the Flashlight Fish and is native to the Indo-Pacific. Flashlight Fish are famous for their bioluminescent organs (photophores) below each eye. The organ accommodates live bioluminescent bacteria that produce a bright white, greenish, or slightly blue light. The bacteria and the fish are truly engaged in a symbiotic relationship. The fish needs the light to find food and communicate to other Flashlight Fish; the bacteria can not survive long-term any place else on Earth but inside the photophores of their respective Flashlight Fish species. In Anomalops, the organ can be rotated outward or inward, likewise flashing the light on and off. By day, most species live in deeper waters. For example, Anomalops katoptron typically spends its time from 200 to 400 meters depth, common around drop offs and sea caves.