A viperfish is a saltwater fish in the genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Chauliodus, with long, needle-like teeth and hinged lower jaws. They grow to lengths of 30 to 60 cm (12 - 24 inches). Viperfish stay near lower depths (250–5,000 feet) in the daytime and shallow at night. Viperfish mainly stay in tropical and temperate waters. It is one of the fiercest predators in the very deep part of the sea and is believed to attack its prey by luring the victim close to itself with a light producing organ.