"its enormous jaws can expand dramatically, creating a balloon-like head..." 10 weirdest, eeriest eels on the planet, including one that generates a deadly 600 volts

While many resemble serpentine fish, other species have evolved with extraordinary adaptations that make them some of the strangest creatures on Earth. From eels with balloon-like jaws and electric powers to species that live buried in the seabed or have lost their eyes entirely, these remarkable fish showcase nature at its most inventive.

Here are 10 of the world's weirdest eels:

Electric eel

Native to the rivers and floodplains of South America, electric eels can generate powerful shocks of up to 600 volts to stun prey and deter predators – although it rarely happens, this is a high enough voltage to kill a human. Electric eels produce electricity in special cells known as electrocytes, found in three separate organs.

• How an electric eel works and the maximum shock it delivers... (you wouldn't want to be be hit by its deadly high-voltage charge)

Despite their name, however, they are not true eels at all, but belong to a group of freshwater fishes known as knifefish.

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Snipe eel

With their impossibly long, curved beaks, snipe eels look more like underwater birds than fish, earning them the nickname “deep-sea ducks”. There are nine known species of snipe eel which dwell in the dark depths of the ocean’s twilight zone.

• It looks like a ridiculous, cartoon duck with a massive beak – and one type is so thin it has to have its anus right up by its throat...

The snipe eel possesses more than 700 vertebrae, which is more than any other known animal. In one species, anatomy becomes even stranger: the anus is positioned near the throat rather than at the tail end of the body.

Gulper eel (or pelican eel)

At first glance, the gulper eel (Eurypharynx pelecanoides) looks much like any other long, snake-like eel. But when feeding time arrives, it transforms into one of the deep sea’s strangest predators as its enormous jaws can expand dramatically, creating a balloon-like head or a pelican-style pouch capable of engulfing surprisingly large prey whole in the darkness of the abyss.

• It has enormous jaws, a tail that glows pink, and can eat prey bigger than itself – meet the deep-sea animal rarely seen by humans

Moray eel

Looking like something out of a horror film, moray eels are among the most recognisable reef predators, lurking in crevices with their mouths permanently agape with jagged teeth. There are over 200 recognised species of moray eels in 16 genera.

• It's longer than a bed, covered in slime and has teeth in its throat – meet this giant hunter of the reef

Unlike most fish, they lack bony gill covers and must continually pump water through their mouths to breathe. They are also equipped with a remarkable adaptation known as pharyngeal jaws – a second set of jaws hidden in the throat that shoots forward to seize prey and pull it deeper into the digestive tract.

The largest moray species is the giant moray eel, which can grow up to 3 metres in length and weighs over 30 kilograms with a thick, muscular body and scaleless, slimy skin.

Garden eel

Garden eels are known for their unique behaviour of burrowing into the sandy seabed, with a colony of garden eels (Heteroconger hassi) resembling blades of seagrass as they sway with the current. These slender fish can reach up to 16 inches in height and spend most of their lives anchored or 'planted' in sandy burrows on the seabed, stretching their bodies into the water column to grab drifting plankton.

Although they can swim freely, at the slightest hint of danger, this shy fish vanishes back into the sand in an instant and they don't often leave their burrows – simply moving to a prospective mate during mating season and interwining with their neighbour.

Snake eel

Snake eels belong to the family Ophichthidae and are named for their striking resemblance to snakes. Most species have elongated bodies, relatively large eyes and small, sharp teeth, adaptations that help them hunt while remaining concealed beneath the sand.

Masters of concealment, snake eels spend much of their time buried beneath sand or mud rather than hiding among rocks and reefs with only their eyes and snout remaining visible, providing perfect camouflage as they lie in wait to ambush passing prey.

Conger eel

Among the largest eels in the world, conger eels are powerful predators that can reach lengths of more than 2.75 metres and weigh over 100 kilograms. They are recognised by their long, snake-like bodies, fused dorsal, tail and anal fins, pointed pectoral fins, forward-facing nostrils, elliptical eyes and grey-blue to grey-brown colouring edged with black along the fins.

Conger eels spend daylight hours sheltering in rocky crevices, holes, shipwrecks and other structures on sandy or rocky seabeds, emerging after dark to hunt for fish, crustaceans and other marine animals. Although most are found at depths of up to 500m, they undertake remarkable journeys into the deep ocean, descending to around 4,000m to spawn.

Blind spiny eel

This weird eel lives in perpetual darkness, which has left the blind spiny eel with little need for sight. Found in deep waters and cave systems in parts of Africa and Asia, these remarkable fish have lost their eyes entirely, relying instead on other highly developed senses to navigate and locate food.

Zebra moray eel

Instantly recognisable thanks to its bold black-and-white stripes, the zebra moray eel is a fish species that lives in coral reefs. A nocturnal hunter, it uses blunt, pebble-like teeth to crush hard-shelled prey such as crabs, sea urchins and molluscs.

Ghost eel (White ribbon eel)

With its pale, almost translucent body and elusive behaviour, the ghost eel (Pseudechidna brummeri) is one of the most mysterious inhabitants of Indo-Pacific coral reefs. Also known as the white ribbon eel, this striking species belongs to the moray eel family and is rarely seen in the open, spending much of its life concealed within narrow crevices and caves among coral formations.

Growing to around 50–76cm (20–30in) in length, the ghost eel has a slender, ribbon-like body that is typically creamy white to pale grey, often marked with subtle darker speckles. Its ghostly appearance provides excellent camouflage against the complex backdrop of reef habitats, helping it avoid predators while remaining hidden from potential prey.

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