The term Flashlight fish can either refer to a family of fish, the Anomalopidae, also known as the Lanterneye fish or any one of a number of individual species, most but not all within that family, most commonly to the Flashlight fish Photoblepharon steinitzi.
The family Anomalopidae is in the order Beryciformes, the Sawbellies. There are some unrelated fish that show similar phenomena to those that get the Anomalopidae their name, and some of these are also called flashlight fish. Notable among these are the Deep Sea Lanternfish, of the family Myctophidae in the order Myctophiformes, of which there are over 200 species.
The family Anomalopidae includes the Splitfin Flashlightfish, Gulf Flashlight fish, Atlantic Flashlight fish, Parmops coruscans, Parmops echinatus, Eyelight fish, Cook Islands Flashlight fish, Chubby Flashlight fish and Spotted Lantern fish
The true flashlightfish, of the family Anomalopidae, have a luminous organ beneath the eyes; Lantern fish have lights along their bodies. The light, which is red in color and called bioluminescence, is generated by bacteria that live in special pouches. It is similar to the glow produced by fireflies.