Eels (Anguilliformes are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800species. Most eels are predators. The term "eel" is also used for some other similarly shaped fish, such as electric eelsand spiny eels, but these are not members of the Anguilliformes order.
Eels begin life as flat and transparent larvae, or leptocephali. Eel larvae drift in the surface waters of the sea feeding on marine snow, small particles that float in the water. Eel larvae then metamorphose into glass eels and then become elvers before finally seeking out their juvenile and adult habitats. Freshwater elvers travel upstream and are forced to climb up obstructions such as weirs, dam walls and natural waterfalls.