Chauliodus sloanii; Print; Viperfish; A viperfish is any species of marine fish in the genus Chauliodus. Viperfish are characterized by long; needle-like teeth and hinged lower jaws. A typical viperfish grows to lengths of 30 to 60 cm (12 to 23.5 in). Viperfish stay near lower depths (250-5; 000 feet [80-1; 520 m]) in the daytime and shallower depths at night; primarily in tropical and temperate waters. Viperfish are believed to attack prey after luring them within range with light-producing organs called photophores; which are located along the ventral sides of its body; and with a prominent photophore at the end of a long spine in the dorsal fin reminiscent of the illicium of the unrelated deepsea anglerfishes. The viperfish flashes this natural light on and off; at the same time moving its dorsal spine around like a fishing rod and hanging completely still in the water. It also uses the light producing organ to communicate to potential mates and rivals.; 1700-1880