Pelican Eel

The pelican eel is a deep-sea fish belonging to the order Saccopharyngiformes, distinguished by an extraordinarily large, loosely hinged mouth resembling a pelican's pouch. Despite its eel-like appearance, it is not a true eel and instead represents a highly specialized deep-sea lineage. It is found in tropical and temperate oceans worldwide at bathypelagic depths, generally between roughly 500 and 3000 meters. The oversized mouth and expandable throat allow it to capture prey disproportionately large relative to its own slender body, an adaptation suited to the unpredictable, food-scarce conditions of the deep ocean. It is one of the most recognizable and frequently referenced examples of deep-sea fish anatomy.

The pelican eel's proportions make it distinctive among deep-sea fishes.

• Mouth: enormous, loose, pouch-like, far larger than the rest of the head and body combined
• Body: small, slender, and dark blackish-brown behind the mouth
• Tail: very long, thin, and whip-like, often bearing a small pink or reddish light-producing organ at the tip
• Eyes: tiny, positioned at the front of the head
• Size: modest overall length, generally under 75 cm despite the mouth's size

It is distinguished from the related gulper eel (Saccopharynx) by its proportionally even larger, more rounded pouch-like mouth and comparatively shorter overall body.

The pelican eel inhabits the deep midwater zone of tropical and temperate oceans worldwide, typically at depths between about 500 and 3000 meters, within the bathypelagic and lower mesopelagic zones. It lives in open water far from the seafloor, in near-total darkness, near-freezing temperatures, and high pressure. Its wide, worldwide distribution reflects the relatively uniform conditions of the deep open ocean across latitudes. It has no strong association with the seafloor or any particular substrate, instead drifting or swimming slowly through open midwater.

The pelican eel is a solitary, slow-moving fish believed to feed opportunistically by expanding its enormous mouth to engulf prey along with a large volume of water, then contracting the pouch to expel the water while retaining any captured crustaceans or small fish. The light-producing organ at the tip of its tail is thought to function as a lure, attracting prey or confusing predators in the darkness of the deep sea. It is not a fast or active pursuit predator, instead relying on its oversized gape to make the most of infrequent prey encounters. Little is known of its reproduction, though it likely follows a pelagic larval life-history pattern typical of deep-sea eels.