Dragonfish
Dragonfish are deep-sea fishes in several families, especially Stomiidae, known for large mouths, sharp teeth, and often bioluminescent organs.
Bioluminescence: The production and emission of light by living organisms through chemical reactions or symbiotic microbes. Many dragonfish produce light with photophores used in signaling, camouflage, or prey attraction.
Stomiidae: A family of deep-sea fishes that includes dragonfishes, viperfishes, and loosejaws. This family contains many fishes commonly called dragonfish.
Black dragonfish: A common name for several dark deep-sea fishes, including species in the genus Idiacanthus. Female black dragonfish can have elongated bodies and luminous barbels.
Dragonet: A small marine fish in the family Callionymidae, unrelated to deep-sea dragonfishes. The similar name can lead to confusion, but dragonets are mostly bottom-dwelling coastal fishes.
Photophore: A light-producing organ found in some animals, especially fishes and cephalopods. Dragonfish arrange photophores along their bodies and, in some species, beneath the eyes.
Aulopiformes: An order of ray-finned fishes that includes lizardfishes, lancetfishes, and several deep-sea groups. Several fish called dragonfish belong to this broader order, outside Stomiidae.
Stoplight loosejaw: A deep-sea stomiid fish, Malacosteus niger, capable of producing red bioluminescence. Its red light and unusually loose jaw exemplify specialized dragonfish predation.
Arowana: A freshwater ray-finned fish in the family Osteoglossidae, sometimes called a dragon fish. In aquarium contexts, “dragon fish” may mean an arowana rather than a deep-sea dragonfish.
Red bioluminescence: Bioluminescence emitted at red wavelengths, which many deep-sea animals cannot detect. Some dragonfish emit red light that can illuminate prey without alerting many other deep-sea animals.
Bathypelagic zone: The ocean layer from about 1,000 to 4,000 meters deep, where sunlight does not reach. Many dragonfish species inhabit this permanently dark ocean layer.