Eel-like fishes can be distinguished from most other fish due to their elongated, snake-like body. There are no ventral fins, and the dorsal, tail and anal fins are usually fused to form a single fin. Freshwater eels (Anguillidae) spend the great majority of their lives in fresh water, but migrate to the ocean to reproduce. Moray, Conger and Snake eels mostly live in coastal waters, on rocky coasts or in coral reefs.
Heat-labile toxins are present in the blood. Practically nothing is known about these toxins.