“Despite their name and snakelike appearance, electric eels are actually knifefish, more closely related to carp and catfish than true eels!”
Electric eels are air-breathing knifefish from slow Amazon and Orinoco waters. Specialized organs generate weak pulses for navigation and communication, then powerful discharges that stun fish, frogs, and other prey.
By An Nguyen · Published · Updated
Electrophorus electricusGymnotiformesGymnotidae
Browse images of the electric eel across habitat, behavior, anatomy, and life stages, including a distribution map of the three Electrophorus species.
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Core article
A closer look at habitat, diet, behavior, reproduction, and conservation.
The electric eel (Electrophorus electricus) is not a true eel at all but an air-breathing South American knifefish that can generate a powerful electric shock. It lives in slow, poorly oxygenated rivers, pools, and flooded forest, using weak electric pulses to navigate and communicate and strong ones to expose, stun, and capture prey. That living battery shapes almost everything about its body and behaviour.
Despite the name, the electric eel is a knifefish (order Gymnotiformes), not one of the true marine eels. Over 80% of its long body is given over to three electricity-generating organs — the Main, Hunter's, and Sachs' organs — built from thousands of stacked disc-like cells called electrocytes that work like the cells of a battery. When the brain triggers a discharge, ion channels in the electrocytes open and the cells fire together. Output varies by species: the strongest ever measured, Electrophorus voltai, reached 860 volts, while this profile covers E. electricus. To keep from shocking itself, the eel is wrapped in thick, scaleless, mucus-coated skin that insulates the body, and its actual organs are packed into just the front fifth of its length.
The electric eel is found only in the fresh waters of northern South America, dominating the Amazon and Orinoco basins across Brazil, Colombia, Venezuela, Peru, Guyana, and Suriname. It thrives in exactly the places most fish avoid: stagnant, muddy floodplains and weed-choked swamps where rotting vegetation strips the water of oxygen. Because rivals struggle to survive there, the electric eel faces almost no competition for prey — the same broad network of waters also supports the giant otter.
Electric eels are carnivores — juveniles take invertebrates, shrimp, and insect larvae, while adults eat fish, crustaceans, and small vertebrates including amphibians. Since their eyesight is nearly useless in murky water, hunting runs entirely on electricity. The eel emits low-voltage pulses (around 10 volts) from Sachs' organ that act like radar, sensing the distortion when a hidden fish enters the field. It then unleashes a high-voltage volley from the Main and Hunter's organs; the shock throws the prey's muscles into involuntary spasm and locks it in place, and the eel — which lacks grasping teeth — swallows it whole.
Electric eels are nocturnal and solitary, reading one another's navigational pulses and steering clear to avoid disputes. Their most surprising trait is obligate air-breathing: the oxygen-poor swamps would suffocate a gill-only fish, so the eel has a heavily vascularised mouth lining and must surface every 10 to 15 minutes to gulp air, absorbing oxygen directly through the tissues of its mouth. Surfacing would expose most fish to predators, but few animals — even caimans or jaguars — risk attacking an electric eel.
Breeding is timed to the dry season, when water drops and isolated pools form. The male builds a nest entirely from his own foamy saliva, and the female lays a large clutch — up to about 17,000 eggs — into the foam, which the male then guards, shocking any intruder that approaches. Eggs hatch in 7 to 10 days, and the first-hatched larvae often eat later, unhatched eggs to survive until the rains return and reflood the plains. Wild electric eels typically live 10 to 15 years.
The electric eel is Least Concern, with robust, stable populations across the vast and largely inaccessible Amazon and Orinoco basins. It has essentially no natural predators, and people rarely hunt it because it is so dangerous to handle. Its long-term security is tied to the rainforest, though: deforestation, the damming of rivers for hydropower, and agricultural pollution all threaten the wetland habitats it depends on.
Kingdom
Animalia
Phylum
Chordata
Class
Actinopterygii
Order
Gymnotiformes
Family
Gymnotidae
Genus
Electrophorus
Species
E. electricus
Despite their name and snakelike appearance, electric eels are actually knifefish, more closely related to carp and catfish than true eels!
Species in the electric eel genus produce high-voltage discharges for hunting and defense; the strongest measured species can reach 860 volts.
They have three special organs in their bodies (the main organ, Hunter's organ, and Sachs' organ) that generate electricity.
Because they live in muddy, low-oxygen waters, electric eels must rise to the surface to breathe air every 10 minutes!
They have very poor eyesight, but they use low-voltage electric pulses like radar to map their surroundings and find food in the dark.
During the dry season, male electric eels build a nest out of their own saliva (spit), where the female lays thousands of eggs.
Select a question to reveal the answer.
An electric eel is a freshwater fish native to South America. It is famous for its ability to produce powerful electric shocks to hunt, navigate, and defend itself.
They have thousands of specialized cells called electrocytes stacked together inside three electric organs. When they spot prey or danger, their brain sends a signal that releases a sudden burst of electricity.
No, it is not a true eel. Electric eels are actually a type of knifefish. They are called eels because of their long, cylindrical, and slimy bodies.
Some electric eels can produce very powerful shocks that stun prey and discourage predators.
Electric eels live in slow-moving freshwater habitats in northern South America, including rivers, floodplains, and swampy pools.
Electric eels are carnivores that eat fish, amphibians, crustaceans, and other small animals they can stun or catch.
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