Electric eel is a long, narrow fish that can produce a strong electric discharge. About 500 species of fish can generate an electric discharge. Of these, the electric eel is the best known and produces the largest amount of electricity. It uses its electric discharge to detect underwater objects, to signal other electric eels, and to stun prey. The electric eel looks like other eels, but it is not a true eel. It is related to catfish and carp.