The Electric Eel (Electrophorus electricus) is a freshwater fish. It is not an eel. It is a Gymnotiforme in the knifefish family. It is related to the Catfish. 

The Electric Eel is an ostarophysan fish because its bladder has two chambers which keeps it buoyant (afloat). It is an air-breather, and must come to the surface to breathe. 

The Electric Eeel has a long, cylindrical, snake-like dark-grey to brownish body. Its underbelly is yellow or orange. It has a fin that runs along its underbelly. It does not have scales like fish. Its mouth is square-shaped.