What is the name of the light-producing organ in many deep-sea animals?

A photophore is a light-producing organ found in many deep-sea animals. It creates bioluminescence through chemical reactions, often involving luciferin and luciferase or related molecules.

Photophores occur in fishes, squid, and other marine organisms. They may appear as tiny spots or more complex structures containing lenses, reflectors, filters, and controls. Animals use them for several purposes, including attracting prey, confusing predators, communicating, or matching the faint light from above.

Not every marine animal that glows has a photophore. Some bioluminescent animals release chemicals into the water, and some host glowing bacteria in specialized organs. Photophores should also be distinguished from eyes: they produce light rather than detect it.