Illustrated here are the larval and adult forms of deep sea angler fish. Deep sea anglers, suborder Ceratioidea, are represented by about 120 species, belonging to eleven different families. Note that the larval form (? Melanocetus sp.) is surrounded by a gelatinous epidermal layer, possibly providing protection, and has not yet developed the lure. In comparison the adult (Melaoncetus sp.) obviously displays its fishing pole lure. Both images were taken by Dr Peter Herring while on board the RS Discovery Vessel.

Deep sea anglers differ from other anglers by the absence of ventral fins. Whereas other anglers live on the bottom from shallow to deep water or, in a few cases such as the Sargassum Angler Fish (Histrio histrio), at the surface, the deep sea ceratioid anglers are mostly midwater forms, ranging in depth from from perhaps one thousand to several thousand feet. Only the females have fishing poles. Since in the depths it would be difficult to see the lure, the tip is usually equipped with a light-producing organ of some kind. It is not known for certain how this light is produced; one suggestion is that luminescent bacteria are responsible.