Conger is a genus of marine congrid eels. It includes some of the largest types of eels, ranging up to 2 m (6 ft) or more in length, in the case of the European conger. Large congers have often been observed by divers during the day in parts of the Mediterranean Sea, and both European and American congers are sometimes caught by fishermen along the European and North American Atlantic coasts.

Eels are ray-finned fish belonging to the order Anguilliformes, which consists of eight suborders, 20 families, 164 genera, and about 1000 species. Eels undergo considerable development from the early larval stage to the eventual adult stage and are usually predators.