There are about 600 species of eels. The most familiar eels are the American eel, European eel, conger eels, and moray eels.

is a smooth-skinned fish with tiny scales. The male is 12 to 18 inches (30 to 45 cm) long, the female is 2 to 6 feet (60 cm to 1.8 m) long. The females migrate from the sea in which they were spawned to the freshwater ponds, lakes, and streams of North and Central America, Bermuda, and the West Indies. After maturing, in about five years, the female begins her migration back to the sea. In the fall the eel enters the sea, and by midwinter reaches a spawning area in the Sargasso Sea, about 200 miles (320 km) southwest of Bermuda. She produces 5,000,000 to 10,000,000 eggs.

The male American eel lives in brackish water near the coast. At spawning time, he migrates to the spawning area, where he meets the female. After spawning, both adults die.

is a freshwater eel that grows to a length of five feet (1.5 m). Like the American eel, it migrates to the Sargasso Sea to spawn. The 3,000-mile (4,800-km) journey takes about three years. The European eel is considered a delicacy.

are saltwater eels found in all warm temperate and tropical oceans. They are aggressive and have been known to attack divers when provoked. The largest species grows to a length of ten feet (3 m).

are often brilliantly colored. A moray eel's body is generally four to five feet (1.2 to 1.5 m) long. Many sharp teeth line the powerful jaws. Moray eels inhabit tropical and warm temperate regions of all the oceans.