Fish & Marine Animals comparison

Eel vs Electric Eel: Key Differences Explained

The short answer

The electric eel is not an eel. It is a South American knifefish, more closely related to catfish and carp than to true eels, and it acquired the name purely from its elongated shape. True eels are marine-spawning fish that migrate enormous distances to reproduce. Electric eels breathe air at the surface and generate strong electrical discharges used for hunting, navigation and defence.

The main difference

The electric eel is a South American knifefish related to catfish, not an eel; true eels are a separate order that migrates to sea to spawn.

The name guarantees the misconception, and correcting it opens up two genuinely remarkable biologies that would otherwise be conflated.

At a glance

Comparison of Eel and Electric Eel across 6 dimensions, with an interpretation of each difference.
What differs	Eel	Electric Eel	What it means
Relatedness	Order Anguilliformes — the true eels	A knifefish, more closely related to catfish and carp than to true eels	The shared name reflects body shape alone.
Electric organs	Absent	Three electric organs generating both weak navigational and strong hunting discharges	Electric organs make up the majority of the electric eel's body length.
Breathing	Gills, with some species able to absorb oxygen through the skin in damp conditions	Obligate air breather — must surface regularly or it drowns	Air breathing suits the oxygen-poor waters it inhabits.
Reproduction	Migrates enormous distances to spawn at sea, with a transparent larval stage	Spawns in fresh water, with the male building a nest of saliva-bound material	Eel migration is one of the most remarkable and least understood in fish.
Habitat	Fresh water, estuaries and ocean depending on life stage and species	Slow, murky, oxygen-poor fresh water in the Amazon and Orinoco basins	The electric eel never leaves fresh water at any life stage.
How prey is found	Acute sense of smell and lateral line detection of water movement	Weak electrical discharges used as an active sensing field	Electrolocation works in murky water where vision is useless.

Relatedness: EelOrder Anguilliformes — the true eels
Electric EelA knifefish, more closely related to catfish and carp than to true eels
The shared name reflects body shape alone.
Electric organs: EelAbsent
Electric EelThree electric organs generating both weak navigational and strong hunting discharges
Electric organs make up the majority of the electric eel's body length.
Breathing: EelGills, with some species able to absorb oxygen through the skin in damp conditions
Electric EelObligate air breather — must surface regularly or it drowns
Air breathing suits the oxygen-poor waters it inhabits.
Reproduction: EelMigrates enormous distances to spawn at sea, with a transparent larval stage
Electric EelSpawns in fresh water, with the male building a nest of saliva-bound material
Eel migration is one of the most remarkable and least understood in fish.
Habitat: EelFresh water, estuaries and ocean depending on life stage and species
Electric EelSlow, murky, oxygen-poor fresh water in the Amazon and Orinoco basins
The electric eel never leaves fresh water at any life stage.
How prey is found: EelAcute sense of smell and lateral line detection of water movement
Electric EelWeak electrical discharges used as an active sensing field
Electrolocation works in murky water where vision is useless.

How they are related

True eels form the order Anguilliformes, a large group including freshwater, moray and conger eels. The electric eel is a gymnotiform knifefish from South America, sitting closer to catfish and carp than to any true eel. Recent work has also split what was long treated as a single electric eel species into more than one.

Telling them apart

Both are elongated, but the details differ. True eels have continuous dorsal and anal fins running much of the body and no pelvic fins. The electric eel has a long anal fin running most of the underside used for undulating propulsion, no dorsal fin, and it surfaces regularly to gulp air — a behaviour no true eel performs.

Elongated fish surfacing regularly to gulp air in murky South American water: electric eel, which is a knifefish. Elongated fish in a European or North American river, or in a reef crevice, with continuous fins along the body: a true eel. The two are not close relatives at all.

Habitat and distribution

Freshwater eels live in rivers and lakes as adults and migrate to sea to spawn, while moray and conger eels are marine. The electric eel lives in slow, murky, oxygen-poor water in the Amazon and Orinoco basins, including swamps and floodplain, conditions in which air breathing and electrolocation are both highly advantageous.

Diet and ecological role

True eels are predators and scavengers taking fish, crustaceans and invertebrates, hunting largely by smell. Electric eels use weak electrical pulses to detect prey in murky water and then deliver strong discharges that cause involuntary muscle contraction in nearby fish, immobilising them before they are swallowed whole.

Behaviour

The freshwater eel life cycle involves migration of thousands of kilometres to specific ocean spawning areas, with larvae drifting back on currents over months or years — a journey only partly understood, since spawning has rarely been directly observed. Electric eels are largely solitary, surfacing every few minutes to breathe and using electricity continuously to sense their surroundings.

Senses and adaptations

The electric eel's three electric organs occupy most of its body. A weak discharge creates a field it monitors for distortions, allowing navigation and prey detection in water where vision is useless, while a strong discharge triggers involuntary muscle contraction in prey. Some individuals have been observed leaping from the water to deliver discharges directly to a threat above the surface.

More on this topic: Animal senses and adaptations.

People and these animals

European and American eel populations have declined severely and are of serious conservation concern, affected by dams, habitat loss, parasites and fishing, and their complex life cycle makes farming from eggs impractical. Electric eels are of research interest for their electrical biology, which contributed historically to the development of the battery, and they are not a major fishery.

Conservation context

European and American eels have declined severely and are of serious conservation concern, with complex life cycles that make recovery difficult and farming from eggs impractical. Electric eel populations are not currently of comparable concern, though Amazon habitat loss affects them. Check the IUCN Red List for current status per species.

What they have in common

Both are elongated fish that move by undulating the body.
Both live in fresh water for at least part of their lives.
Both are predators that locate prey without relying on vision.
Both are affected by freshwater habitat degradation.

Key differences

The electric eel is a knifefish related to catfish, not a true eel.
Electric eels generate strong and weak electrical discharges; true eels generate none.
Electric eels must surface to breathe air, while true eels use gills.
True eels migrate to sea to spawn, whereas electric eels spawn in fresh water.
Electric eels are confined to the Amazon and Orinoco basins.

Where people go wrong

Assuming the electric eel is a kind of eel.
Expecting all elongated fish to be closely related.
Believing electric eels use only strong discharges, when weak sensing pulses are constant.

Frequently asked questions

Is an electric eel actually an eel?

No. It is a knifefish from South America, more closely related to catfish and carp than to any true eel. The name comes purely from its elongated body shape. True eels belong to a separate order and differ in fin arrangement, breathing, reproduction and habitat. Recent work has also split what was long treated as one electric eel species into more than one.

How does the electric eel generate electricity?

Through three specialised organs made of stacked cells that each produce a small voltage, arranged so the voltages sum — the same principle as cells in a battery. Weak discharges are used continuously for navigation and prey detection in murky water, while strong discharges cause involuntary muscle contraction in nearby fish. The organs occupy most of the animal's body length.

Why do true eels migrate so far to spawn?

The full answer is still unknown, which is part of what makes it remarkable. European and American eels travel thousands of kilometres to spawning areas in the Sargasso Sea, and their transparent larvae drift back on ocean currents over months or years. Spawning has rarely been directly observed. The migration is generally explained as a legacy of continental positions when the pattern first established.

Can an electric eel drown?

Yes. It is an obligate air breather, taking oxygen at the surface through a specialised vascularised mouth lining, and it will drown if prevented from surfacing. The adaptation suits the warm, stagnant, oxygen-poor water it inhabits, where gill breathing alone would be inadequate. True eels breathe with gills, and some can additionally absorb oxygen through the skin in damp conditions.

Read the full profiles

Sources and methodology

How this comparison is built: FaunaHub comparisons are assembled from the sourced animal profiles behind them rather than written as standalone claims. Figures such as size, mass, and lifespan are typical ranges that vary by subspecies, population, region, sex, age, and — where relevant — whether an animal lives in the wild or under human care, so they are presented as ranges rather than fixed values. Where a common name covers a group rather than a single species, the page says so instead of implying a species-to-species match. Conservation status changes over time and should be confirmed against the current IUCN Red List. Dimensions that could not be supported from the underlying profiles are omitted rather than filled in.

What this page does not do: it does not rank the two animals, predict the outcome of a confrontation, or present either one as stronger, smarter, or better. It is not veterinary, medical, first-aid, handling, capture, hunting, or pest-control guidance. For an animal in your care, or any situation involving injury, contact a qualified veterinarian, your local wildlife authority, or emergency services.

Sources and further reading

Authoritative references used for general educational context. External links open in a new tab. These sources do not endorse FaunaHub.

UniversityAnimal Diversity Web — Anguilliformes (true eels) — University of Michigan order-level account
GovernmentNOAA Fisheries — Marine Life — U.S. government science agency for marine species and habitats
ReferenceEncyclopaedia Britannica — Animals reference — Editor-reviewed encyclopedia overview entries
UniversityAnimal Diversity Web — Electrophorus electricus (electric eel) — University of Michigan species account
ReferenceBritannica — Electric eel — Editor-reviewed encyclopedia entry
Wildlife referenceIUCN Red List of Threatened Species — Authoritative source for current conservation status
UniversityAnimal Diversity Web — University of Michigan Museum of Zoology — Peer-edited reference accounts for animal species
ReferenceWoRMS — World Register of Marine Species — Authoritative register of marine species names

Last updated: 2026-08-04