From The Aquarium Wiki
The term "Eel" can apply to several groups of fish. The most well known being the Electric Eel, American Eel and Moray Eels as "true Eels". The term "Eel" can be applied to any long and slender snake-like fish however as a selling point, such Kuhli Loaches and Dojo Loaches.
Eels can include: