Electric Eel Identification Guide

Key identification features

• Long, cylindrical body that flattens slightly toward the tail, resembling a true eel despite being a knifefish
• No dorsal or pelvic fins present
• A long anal fin running nearly the entire length of the underside, used to undulate and swim, including backward
• Small, rounded pectoral fins located just behind the head
• Uniform dark gray, brown, or olive coloring with a lighter throat and underside

Common look-alikes

• True freshwater eel: has visible gill slits and small pectoral fins used differently, and lacks a strong electric organ
• Black ghost knifefish: a smaller relative with a slender, tapering tail and a much weaker electric field
• Moray eel: lives in marine reef habitats rather than freshwater rivers and has a continuous dorsal-tail-anal fin fringe instead of just a long anal fin

Where you'll see one

Electric eels inhabit slow-moving freshwater streams, floodplains, and swampy backwaters of the Amazon and Orinoco river basins in South America. They must periodically rise to the surface to gulp air, since much of their oxygen intake comes from breathing rather than through gills alone.