/Bioluminescent communication. Communication by the production of light occurs commonly in vertebrates and invertebrates in the oceans, particularly at depths (e.g. angler fish). Two well known forms of land bioluminescence are fireflies and glow worms. Other insects, insect larvae, annelids, arachnids and even species of fungi possess bioluminescent abilities. Some bioluminescent animals produce the light themselves whereas others have a symbiotic relationship with bioluminescent bacteria.
The Pacific blackdragon is a deep sea fish, that can be found up to depths of up to 3,300 ft. Female blackdragons are about two feet long and have fang like teeth and a long chin whisker. They are black on the outside, aswell as on the inside to prevent light from swallowed bio-luminescent prey shining out. The males are small, about three inches in length, and brownish in color. They have no teeth, no chin barbel and no stomach. Unable to eat, the male lives only long enough to mate.