A
photophore is a light-emitting organ which appears as
luminous spots on various marine animals, including
fish and
cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors. The
light can be produced from compounds during the
digestion of prey, from specialized
mitochondrial cells in the organism, called
photocytes ("light producing" cells), or, similarly, associated with
symbiotic bacteria in the organism that is
cultured.