Last updated: October 13, 2022
Verified by: AZ Animals Staff
© Peter Southwood / CC BY-SA 3.0 – License / Original

Can use slime to suffocate marine predators or escape capture

Hagfish Scientific Classification


Read our Complete Guide to Classification of Animals.

Hagfish Conservation Status

Hagfish Locations

Hagfish Locations

Hagfish Facts

Bottom-dwelling invertebrates
Group Behavior
  • Solitary
Fun Fact
Can use slime to suffocate marine predators or escape capture
Estimated Population Size
Biggest Threat
Harvesting for leather and food
Most Distinctive Feature
Other Name(s)
Slime eel, slimy eel
Every ocean
Birds, mammals
Common Name
Number Of Species

Hagfish Physical Characteristics

  • Grey
  • Pink
Skin Type
40 years
0.85-1.4 kg (1.8-3.1 lb)
4cm (1.6in)-81.28cm (32in)

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Hagfish, also known as slimy eels or slime eels, are so named because they produce slime

However, they are not actually eels but eel-like fish that have jawless mouths along with lampreys. They are considered to be the most disgusting animals and are important for commercial and food purposes. The hagfish’s habitat is all the world’s oceans, with each species having a different range.

5 Incredible Hagfish Facts!

  • These fish are the only animals that have a skull but no spinal column, although they do have rudimentary vertebrae.
  • They can absorb nutrients through their skin.
  • Their slime allows them to escape capture when they tie themselves into an overhand knot.
  • Their slime clogs up marine predators’ gills, suffocating them so they will release the hagfish.
  • The hagfish’s loose skin allows for whole-body flexibility to enable it to tie itself into knots without injury.

Hagfish Classification and Scientific Name

There are 6 genera and 1 family of hagfish (Myxinidae), although sometimes they are classified into 2 families, the other being Eptatretidae. All species have the common characteristics of a jawless mouth and a cartilaginous skull with no spinal column. They are agnathans, or jawless fish, in the superclass Cyclostomata (Agnatha). Their subphylum is Vertebrata, because although they have no spinal column, they have rudimentary vertebrae. Besides the genera Myxini and Eptatretus, other genera include Paramyxine, Notomyxine, Neomyxine, and Nemamyxine.

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Hagfish Species

There are approximately 70-82 species, with the number varying depending on the source due to the continuous discovery of new species. The most studied species, with the scientific name Myxini glutinosa, is also called the Atlantic hagfish. Other species are the Goliath (scientific name Eptatretus goliath), Pacific or California hagfish (scientific name Eptatretus stoutii), and the black hagfish (Eptatretus deani).

Hagfish Appearance

All these fish species have the common characteristics of long, slender bodies with a pinkish-grey, blue or purple color depending on the species, and sometimes covered in spots. They all also produce a thick, sticky slime from 100 glands on both sides of their bodies. Their weight ranges from 0.85 to 1.4 kg (1.8 to 3.1 lb) with a length of 4cm (1.6in)-81.28cm (32in), but typically 50cm (19.7in)

There are several other unique characteristics:

  • Hagfish are one of the few animals have multiple hearts. They possess three accessory hearts, no cerebrum or cerebellum, a single nostril, and a cartilaginous skull.
  • A tooth plate that protracts and retracts in lieu of jaws, 2 parallel rows of rudimentary, pointed teeth which repeatedly get re-absorbed and regrown, a rasping tongue, and a horizontally-moving, funnel-shaped mouth.
  • Several pairs of tentacles in various places on the body serve mechanosensory and chemosensory functions.
  • A reduced pair of eyes appearing as pigmented spots on the back of the head behind the oral region, under the translucent skin, and in front of the gill-bearing branchial region.
  • What differentiates these fish from eels is the lack of paired fins, since they have only the caudal (tail) fin.
  • Internally, their respiratory system is unique, with the presence of a sinus system through which the organs absorb blood from the veins and other blood vessels.
  • They have no stomach but the food they consume is instead enclosed in a permeable membrane.

The Atlantic hagfish can grow up to 95 cm in length while the Goliath Hagfish can reach 127.5 cm. The Goliath hagfish is the largest species, with a specimen measuring 127 cm (4 ft 2 in). Myxine kuoi and Myxine pequenoi reach up to 18 cm (7.1 in), while other species are as small as 4 cm (1.6 in).

The species of the genus Eptatretus are seven-gilled hagfishes. The Atlantic and Pacific hagfish differ in two ways: The Atlantic hagfish has muscle fibers in its skin and its resting position is stretched, while that of the Pacific hagfish is coiled.

Six gill hagfish Eptatretus hexatrema at the wreck of the Oakburn at Duiker Point on the Cape Peninsula

©Peter Southwood / CC BY-SA 3.0 – License

Hagfish Distribution, Population, and Habitat

These fish are present in all the world’s oceans and all species live in cold saltwater, with their range or ocean varying depending on the species. The habitat of the species in the Eptatretus genus is the Pacific Ocean, with that of the Far Eastern inshore hagfish (Eptatretus burgeri) being the Northwest Pacific. The habitat of the Myxinidae family is all the world’s oceans, and that of Eptatretidae is everywhere except the North Atlantic. They burrow into the ocean floor or into dead and dying fish, living in cold, low waters with a temperature of 15°C and depth range of 52-5,600ft (15.85-1,800m), but typically 4,000ft (1,219m).

Hagfish Predators and Prey

Hagfish are scavengers and parasitic, with a carnivorous diet. They prefer to feed on or parasitize live prey, although they will scavenge on dead or dying creatures when given the opportunity. While feeding, they use their rasping tongues to pull their prey into their mouths.

What do hagfish eat?

Hagfish typically feed on bottom-dwelling worms and other invertebrates, whales, and fish. They can absorb nutrients through their skin and produce slime when they feed.

What eat hagfish?

Hagfish have few marine predators due to their slime, which helps them to escape predators, as well as the ability to squeeze through openings that are less than half their body width, which not only helps them to escape predators but to scavenge. Their predators are mostly varieties of birds and mammals, with humans posing a threat to 20% of the population according to the IUCN.

Hagfish Reproduction and Lifespan

Hagfish are a sexually dimorphic species with a ratio of up to 100:1 in favor of females. Some species are hermaphroditic. Females lay anywhere between 1-30 tough eggs that stick to each other with Velcro-like ends. The gestation period is typically 11 months, and there is no larval stage, unlike lampreys. Not much else is known about their reproductive behavior due to the difficulty in laboratory breeding. Regardless, they can live up to 40 years in the wild and 17 in captivity

Hagfish in Fishing and Cooking

Hagfish have important commercial uses.

For one, they are eaten in Korea and Japan. In Korea, they are typically skinned before being grilled or stir-fried and are considered an aphrodisiac by the men. In Japan, hagfish serve as an alternative to tofu, due to the slime that can bind a large amount of liquid with little to no heating. Curious eaters can obtain hagfish in the United States from fishermen in California.

Hagfish flesh is chewy with a mild yet distinct taste and an unpleasant aftertaste. To prepare Korean-style, slice down the middle, remove the digestive tract, and marinate in Korean barbecue sauce. Place the raw fish on a hot plate and cook, slicing with scissors, and serve the cooked fish with lettuce and gochujang (red chili paste). The head is typically left on the fish and offered as an honor to guests. Alternately, the fish can be eaten raw, and they are also popular in their raw form.

Hagfish skin is used as a durable leather in several clothing accessories including wallets, belts and shoes. It is typically called “eel skin.”

Hagfish live on or near the bottom of the ocean floor. For this reason, fishing is difficult in the presence of hagfish, since they can spoil or consume the catches within fishermen’s deep dragnets before they can pull them to the surface.

Hagfish Slime

Although the thick, sticky substance hagfish produce is called slime, it’s actually not. Its characteristics are instead a milky, fibrous mucus. The species Myxini glutinosa was named for it, with the word “glutinosa” in Latin meaning glutinous or gummy. Hagfish produce slime while they eat, while burrowing, or while escaping from predators in conjunction with an overhand knot from head to tail. The slime is often used as a substitute for egg whites.

Hagfish Population

The population of all hagfish species is unknown.

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Hagfish FAQs (Frequently Asked Questions) 

What is a hagfish?

A hagfish is an eel-like, jawless fish.

Where do hagfish live?

Hagfish live in all oceans, with their habitat range depending on the species.

What do hagfish eat?

Hagfish eat worms and other invertebrates, fish, and whales.

What is hagfish slime used for?

It is an egg white substitute.

Can you eat hagfish?

Yes, you can eat hagfish, but it is an acquired taste.

What Kingdom do Hagfish belong to?

Hagfish belong to the Kingdom Animalia.

How do Hagfish have babies?

Hagfish lay eggs.

What are the differences between olive sea snakes and hagfish?

The key difference between the olive sea snake and the hagfish is that olive sea snakes are reptiles, and hagfish are fish. Olive sea snakes breathe air, whereas hagfish breathe water. Hagfish live on the murky ocean bottom and have no jaws, whereas olive sea snakes live among coral reefs and have jaws.

What are the differences between lampreys and hagfish?

The key difference between lampreys and hagfish is that lampreys have uniquely adapted mouths for getting nutrients from their prey’s blood while hagfish are scavengers. While the two fish are superficially very similar, they have differences in terms of diet, defense mechanisms, and anatomy.

What are the key differences between an orca and a hagfish?

The greatest differences between an orca and a hagfish can be found in their size and morphology. The hagfish resembles a small eel that measures between 1 and 32 inches and weighs up to 3.1 pounds, and the orca is the largest member of the dolphin family, weighing up to 12,000 pounds and growing up to 26 feet in length.

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.

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  2. Aquarium of the Pacific, Available here: https://www.aquariumofpacific.org/onlinelearningcenter/species/pacific_hagfish
  3. Smithsonian Magazine, Available here: https://www.smithsonianmag.com/science-nature/14-fun-facts-about-hagfish-77165589/
  4. Wired, Available here: https://www.wired.com/2014/11/creature-feature-10-fun-facts-hagfish/
  5. Berkeley University, Available here: https://ucmp.berkeley.edu/vertebrates/basalfish/myxini.html
  6. Animals, Available here: https://animals.net/hagfish/
  7. Britannica, Available here: https://www.britannica.com/animal/hagfish
  8. Alaska Department of Fish and Game, Available here: http://www.adfg.alaska.gov/index.cfm?adfg=hagfish.main
  9. Wiley Online Library, Available here: https://onlinelibrary.wiley.com/doi/abs/10.1002/aqc.1202
  10. IUCN, Available here: https://www.iucn.org/content/depletion-body-snatchers-bad-news-marine-environment
  11. Loveland Living Planet Aquarium, Available here: https://thelivingplanet.com/animal/pacific-hagfish/
  12. Sea and Sky, Available here: http://www.seasky.org/deep-sea/atlantic-hagfish.html
  13. Owlcation, Available here: https://owlcation.com/stem/The-Hagfish-A-Strange-Animal-With-a-Useful-Slime
  14. Your Article Library, Available here: https://www.yourarticlelibrary.com/fish/anatomy-and-physiology/hagfish-anatomy-and-physiology-intro-digestive-system-and-other-organs/88197

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