Electric eel

What it is

The electric eel belongs to the genus Electrophorus, a group of neotropical freshwater fish found in South America. Although they share a name with true eels, they are actually knifefish in the order Gymnotiformes. They possess long, stout bodies that are cylindrical at the front and flattened near the tail. Their skin is smooth, thick, and ranges from brown to black, often with a yellow or red underbelly. They lack scales and have small eyes with poor vision. Instead, they rely on electrolocation using receptors in their head to navigate and hunt in dark, muddy waters.

Where it lives

These fish inhabit the northern part of South America, including regions in Brazil, Suriname, and Peru. The three species have largely non-overlapping distributions. Electrophorus electricus is found in the Guiana Shield uplands, while E. voltai ranges from the Brazilian shield northwards. Electrophorus varii occupies central lowland areas. They live on muddy river bottoms and in swamps, favouring deep shade. They can tolerate water with very low oxygen levels by swimming to the surface to breathe air directly.

How it lives

Electric eels are nocturnal obligate air-breathers that primarily eat fish. E. voltai hunts armoured catfish and has been found with toxic caecilians in its stomach, suggesting resistance to their secretions. Some specimens hunt in packs, herding shoals of tetras before striking together. They use electroreceptors derived from the lateral line to sense water movements and locate prey. Their vital organs are packed near the front, sequestered from the electric organs that generate shocks up to 860 volts. They can survive on land for hours if their skin remains wet.

Breeding and life cycle

Reproduction occurs during the dry season, typically from September to December, when water levels drop and fish gather in small pools. Males build nests using saliva, and females deposit around 1,200 eggs. Mothers continue laying eggs throughout the season, making them fractional spawners. Larvae hatch after seven days and consume leftover eggs until they reach 9 cm. Adults provide parental care for four months, with males protecting the nest and young. Males grow larger than females and become reproductively active at 1.2 m.

Fish and people

The electrical capabilities of electric eels were first studied in 1775, which contributed to the invention of the electric battery in 1800. Their ability to generate high-voltage shocks has made them subjects of scientific research into bioelectricity and neurobiology. While not commonly farmed or kept as aquarium pets due to their size and power, they hold cultural significance in indigenous Tupí language as puraké. There are no major commercial fisheries targeting them, but they remain important for understanding vertebrate evolution and electrical physiology.

Status and threats

The International Union for Conservation of Nature lists the electric eel as Least Concern. However, specific population data is limited. Habitat loss due to deforestation, dam construction, and pollution poses potential threats to their muddy river and swamp environments. The split into three species in 2019 means conservation status may need individual assessment for each lineage. Current protections vary across their range in South America, but no immediate widespread endangerment is recorded.

Relatives and look-alikes

Electric eels are closely related to other gymnotiform knifefish, particularly the genus Gymnotus, such as the banded knifefish. They form a clade of strongly electric fishes within the order Gymnotiformes. Unlike most knifefish, which are weakly electric and use electricity only for sensing, electric eels can deliver powerful shocks. They are often confused with true eels (Anguilliformes) due to their elongated body shape, but they are not closely related taxonomically.

Questions people ask about Electric eel

Good reading and sources

• Electric eel on WikipediaEncyclopedia
• More photos on Wikimedia CommonsPhotos
• Wikidata recordOpen data