American Eel Identification Guide

Key identification features

• Long, snake-like, cylindrical body that flattens slightly toward the tail
• Small, pointed head with a slightly protruding lower jaw and small eyes
• Continuous dorsal, caudal, and anal fins forming one unbroken fin margin, with the dorsal fin origin set well behind the pectoral fins
• Smooth-looking skin covered in tiny embedded scales, giving a slimy, scaleless appearance
• Color shifts with life stage: olive-brown to yellowish on the back and sides as a "yellow eel," turning silvery-gray with a darker back as it matures into the migratory "silver eel" phase

Common look-alikes

• European eel: nearly identical in appearance; the most reliable field distinction is geography, since American eel occurs only in the Western Atlantic while European eel inhabits European and North African waters
• Conger eel: has a more robust body, a dorsal fin that begins much closer to the head near the pectoral fins, and lacks the small scales embedded in true freshwater eel skin
• Snake eels: taper to a hard, finless point at the tail rather than a continuous fin fringe, and burrow tail-first, unlike the American eel's fully finned tail

Where you'll see one

American eels are catadromous, spending most of their lives in fresh and brackish rivers, streams, and estuaries along the Atlantic coast of North America before migrating to the Sargasso Sea to spawn.