Eel

Eels are elongated fish, ranging in length from 5 cm in the one-jawed eel (Monognathus ahlstromi) to 4 m in the slender giant moray. Adults range in weight from 30 g to well over 25 kg. They possess no pelvic fins, and many species also lack pectoral fins. The dorsal and anal fins are fused with the caudal fin, forming a single ribbon running along much of the length of the animal.

Most eels live in the shallow waters of the ocean and burrow into sand, mud, or amongst rocks. A majority of eel species are nocturnal, thus are rarely seen. Sometimes, they are seen living together in holes, or “eel pits”. Some species of eels also live in deeper water on the continental shelves and over the slopes deep as 4,000 m. Only members of the Anguilla regularly inhabit fresh water, but they, too, return to the sea to breed.

The heaviest true eel is the European conger. The maximum size of this species has been reported as reaching a length of 3 m and a weight of 110 kg. Other eels are longer, but do not weigh as much, such as the slender giant moray which reaches 4 m.