For about 250 years scientists counted only one kind of electric eel. As of November 2026, they know of at least three species. One is named Electrophorus varii for the late Smithsonian fish scientist Richard Vari, and another is named E. voltai for Alessandro Volta. An electric eel is a fish, but it is not a true eel. It is more closely related to catfish and carp than to true eels. Poraque is an Indigenous Brazilian word for electric eel.

An electric eel has a long, snake-like body and a flat head. It has thick skin with no scales. It swims with one long fin along its underside, and it can swim forward and backward. It grows to be about 8 feet, or 2.5 meters, long. As of November 2026, the heaviest published weight is 20 kilograms (44 pounds). Electric eels live in rivers and ponds in South America, in quiet, slow-moving, muddy water in the Amazon and Orinoco river basins.

An electric eel has gills like other fish, but it cannot live without air. The water where electric eels live can be muddy and low in oxygen, so the eels breathe air. An eel has to come to the surface for a breath at least every ten minutes. It gets about 80 percent of its oxygen by gulping air at the surface. In the dry season the water in the rivers drops, and eels can be left in small pools. Electric eels also live in muddy lowland waters, where the water is slow and murky.

An electric eel makes electricity with special cells called electrocytes, and it has thousands of them. The electrocytes work like a stack of batteries. An eel's electric organ is made of hundreds of thousands of flat cells connected in a line, like a long string of battery cells. An electric eel has three electric organs, and most of its body is electric organ. Electric eels inspired the design of the first battery, in 1799.

Electric eels hunt at night. An eel does not see well, so it uses a weak electric charge to find its way in dark water. Most of the time an electric eel makes only a weak charge, about 10 volts or less. At rest an eel gives off very little electricity, and it gives off more when it moves around or feeds. When an electric eel thinks food is nearby, it sends out two quick pulses called a doublet. The doublet makes hidden fish twitch. After the shock, the eel opens its mouth to make suction and takes in its food. It eats fish and other small animals.

Words to know

• species: kind of animal
• doublet: two quick pulses
• suction: pulling force
• electrocytes: power cells
• poraque: Brazilian name