Electric eel
Neotropical freshwater fish that generate powerful electric shocks.
Electric eels are a genus, Electrophorus, of neotropical freshwater fish from South America in the family Gymnotidae. Despite their common name, they are not true eels but belong to the knifefish order Gymnotiformes. They are renowned for their ability to generate powerful electric shocks, reaching up to 860 volts, which they use to stun prey. Their electrical capabilities were first studied in 1775, a line of inquiry that contributed to the invention of the electric battery in 1800. For over two centuries, the genus was thought to contain a single species, Electrophorus electricus, but in 2019 it was split into three distinct species: E. electricus, E. voltai, and E. varii. These species differ in head shape and skeletal structure, with E. voltai being the strongest bioelectricity generator in nature. Electric eels are nocturnal, obligate air-breathers with poor vision, relying instead on electrolocation to navigate and hunt, primarily feeding on fish. They grow continuously throughout their lives, adding vertebrae to their spinal column, and males are larger than females. Some captive individuals have lived over 20 years. The genus was originally described by Carl Linnaeus in 1766 as Gymnotus electricus, and later moved to its own genus, Electrophorus, by Theodore Gill in 1864. The name derives from Greek words meaning "electricity bearer." Their lineage split from their closest relatives, the knifefish genus Gymnotus, during the Cretaceous period. The three species have largely non-overlapping distributions in northern South America, occupying different habitats from upland waters to lowland streams and swamps, where they tolerate low-oxygen conditions by surfacing to breathe air.
- Scientific name
- Electrophorus
- Class
- Actinopterygii
- Order
- Gymnotiformes
- Family
- Gymnotidae
- Habitat
- Northern South America, muddy river bottoms and swamps
Lore & Background
Electric eels are elongated, snake-like freshwater fish that can reach large sizes, with males growing larger than females, and they continue to grow throughout their lives by adding vertebrae to their spinal column. Their bodies are not closely related to true eels but instead belong to the knifefish order. The three recognized species—*Electrophorus electricus*, *E. voltai*, and *E. varii*—look very similar in body shape and coloration, but differ in head shape: *E. electricus* has a U-shaped head with a flattened skull, *E. voltai* has a more egg-shaped head with a flattened skull, and *E. varii* has a thicker skull and cleithrum with a more variable head shape. They inhabit the northern part of South America, with *E. electricus* confined to the Guiana Shield uplands, *E. voltai* ranging from the Brazilian shield northward in upland waters, and *E. varii* found in central lowland areas including streams, grasslands, ravines, ponds, and swamps with muddy bottoms and deep shade. These fish are nocturnal, obligate air-breathers that tolerate low-oxygen water by surfacing to breathe. They have poor vision but compensate with electrolocation. Their defining characteristic is the ability to generate powerful electric shocks, with *E. voltai* being the strongest bioelectricity generator in nature, delivering up to 860 volts. They primarily eat fish, including armoured catfish and cichlids, and *E. voltai* has been observed hunting in packs, herding prey before striking. Some captive individuals have lived over 20 years.
Reader's Guide
Electric eels are not true eels but belong to the knifefish order Gymnotiformes. They possess three pairs of electric organs that generate both low-voltage discharges for electrolocation and high-voltage shocks, reaching up to 860 volts, used to stun prey. Their electrical capabilities were first studied in 1775, a line of inquiry that contributed to the invention of the electric battery in 1800. These fish are nocturnal and obligate air-breathers, inhabiting muddy river bottoms and swamps in northern South America, where they tolerate low-oxygen water by surfacing to breathe. They have poor vision and rely on electrolocation to navigate and hunt, primarily feeding on fish such as armoured catfish and cichlids. One species, *E. voltai*, has been observed hunting in packs, herding shoals of tetras before launching joint strikes. Electric eels grow continuously throughout their lives, adding vertebrae to their spinal column, with males growing larger than females. Some captive individuals have lived for more than 20 years. The genus was long considered to contain a single species, but in 2019 it was split into three distinct species based on DNA, anatomy, and electrical ability. These species have largely non-overlapping ranges: one is confined to the Guiana Shield, another to the Brazilian shield, and the third inhabits lowland regions with variable habitats, including streams, ponds, and areas with dramatic seasonal water level changes.
Did You Know?
- They are not closely related to true eels but are members of the knifefish order Gymnotiformes.
- Electric eels are obligate air-breathers and can survive on land for some hours if their skin is wet.
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