The American eel has a slender, snakelike body with a small pointed head. Its back and sides are brown or green, and the belly is yellow or white. The dorsal, tail and anal fins form a single, continuous fin. The eel’s body appears to be smooth because its scales are so small. The rapid serpentine movement and the smooth, slime-covered skin make the eel almost impossible to hold when captured, giving rise to the “slippery as an eel” saying. Eels are most active at night.