Production of light by photogenic organisms, such as in fireflies, glow worms, crustaceans, coelenterates, fungi, dinoflagellates and bacteria. Light producing dinoflagellates and bacteria may live in symbiosis with animals such as fish. Some fish (e.g. Myctophidae or Lantern fishes) posses light organs (photophores) which are filled with photogenic organisms. Other animals are self luminous having special photogenic organs containing photocytes. The chemical responsible for light emittance is lucifering which is reduced by ATP and the enzyme luciferase and oxidized by free oxygen releasing light. Bioluminescence plays a role in mating and prey attraction and occurs in many (deep)sea animals.