Eels are teleost fish. They have long and narrow bodies like snakes. Adult eels can be as short as 10 cm or as long as 3 m. It depends on their species. The large eels can weigh up to 65 kg.
Eels have fewer fins than other fish. They do not have all the belly and chest fins. The back and anal fins are long and usually connected to the tail fin. The fins do not have spines.
The shoulder bones are separate from the skull. The scales have smooth edges or are absent.