What are the most dangerous eels?

The moray eel

Eels look like sea snakes, but sea snakes are not even fish - they're reptiles. Sea snakes breathe air with lungs. Eels are fish, and the moray eel is able to severely injure a swimmer with it's long, sharp teeth.

The electric eel

This most amazing eel can actually give a swimmer an electric shock. The electric eel's shock is quite strong, and could be fatal if a swimmer lost consciousness under the water.

Source: America Zoo