Earth’s deep sea

The gulper eel: a deep-sea fish that is mostly mouth

By the Fish of Ganymede team · 2 min read · Updated 3 November 2026

Gulper eel: an alien gulper fish with a huge mouth and a whip-like tail from Fish of Ganymede

The gulper eel looks like a joke: a huge mouth on a thin body that trails off into a long whip of a tail. It lives in the dark far below the surface, and almost everything we know about it comes from fish caught in deep nets and a few lucky videos from submarines.

Quick facts

Scientific name: Eurypharynx pelecanoides, the only species in its genus.
Other names: pelican eel, pelican gulper, umbrella-mouth gulper.
Size: usually up to about 75 cm, and most of that is tail.
Depth: mostly 500 to 3,000 metres down.
Where: tropical and temperate oceans around the world.
Food: mainly small shrimp-like crustaceans, plus some small fish and squid.

That enormous mouth

The gulper’s jaws are far longer than its skull and only loosely hinged, with a stretchy pouch of skin between them, a bit like a pelican’s bill. That is where the name pelican eel comes from. When it opens its mouth, it becomes a net several times wider than its body.

It probably lunges at a cloud of small animals, gulps them in with a lot of water, then closes its mouth and pushes the water out through its gill slits. Its stomach can stretch too, which helps in a place where meals are rare.

An alien gulper fish with a huge mouth and a whip tail, drawn by the game — An in-game Gulper: mostly mouth.

A glowing tail

The tip of the long tail carries a light organ that can glow pink or red and flash. Nobody has seen exactly how it is used, but scientists think it may lure prey toward that giant mouth. The gulper’s eyes, by contrast, are tiny.

Caught on camera

Living gulper eels are rarely seen. In 2018 the research ship Nautilus filmed one off Hawaii puffing its mouth up like a balloon, then shrinking back to an eel shape and swimming away. The clip went around the world, because it showed how strange the animal really looks alive.

Is it really an eel?

Not a true eel, but a cousin. Gulper eels belong to a small group of deep-sea fish related to true eels, and like eels they start life as see-through, leaf-shaped larvae that drift in the ocean. They have no scales, and little is known about how they find a mate in the dark.

The Gulper in Fish of Ganymede

The game’s Gulper body plan is based on it: an epic body plan with an enormous maw that lives in the deeper zones of Ganymede’s ocean. Read about its neighbours, anglerfish, dragonfish and more, or catch one yourself, free in your browser.

Questions

Is the gulper eel dangerous to humans?

No. It lives far deeper than people dive, and eats small animals like shrimp and small fish.

Why is it called a pelican eel?

Its huge lower jaw and stretchy pouch of skin look like a pelican’s bill.

How big is a gulper eel?

Usually around 75 cm long, but most of that is a thin tail. The mouth is huge compared with the rest of the body.