Eel

Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 19 families, 111 genera, and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage, and most are predators. The term "eel" is also used for some other eel-shaped fish, such as electric eels (genus Electrophorus), spiny eels (family Mastacembelidae), and deep-sea spiny eels (family Notacanthidae). These other clades, however, evolved their eel-like shapes independently from the true eels. Eels live both in salt water and fresh water and some species are catadromous. == Description == Eels are elongated fish, ranging in length from 5 cm (2 in) in the one-jawed eel (Monognathus ahlstromi) to 4 m (13 ft) in the slender giant moray. Adults range in weight from 30 g (1 oz) to well over 25 kg (55 lb). 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. Eels swim by generating body waves which travel the length of their bodies.