Eel Facts

About the eel

True eels form the order Anguilliformes, which holds eight suborders, 20 families, 164 genera and roughly 1,000 species. They change a great deal between the early larval stage and adulthood. The word eel also gets used for other snake-shaped fish, like electric eels, swamp eels, slime eels and deep-sea spiny eels. Most of those groups evolved their long shape on their own, separate from true eels.

The exception is the deep-sea spiny eels: their order, Notacanthiformes, is the sister group of true eels. As a rule, most eels live in the sea. A few break that pattern. Members of the genus Anguilla and the freshwater moray spend most of their lives in fresh water, the rice-paddy eel spawns in fresh water, and the freshwater snake eel Stictorhinus also lives away from the sea.

Did you know?

• Electric eels belong to the genus Electrophorus, not to the true eels.
• Slime eels belong to the class Myxini.
• Swamp eels make up their own order, Synbranchiformes.