European congers have an average adult length of , a maximum known length of around  (possibly up to  for the largest specimens), and maximum weight of roughly , making them the largest eels in the world by weight. They can be rivaled or marginally exceeded in length by the largest species of moray eel but these tend to be slenderer and thus weigh less than the larger congers.
European congers have an average adult length of , a maximum known length around (possibly up to  for the largest specimens), and a maximum weight of roughly . This makes them among the heaviest eels in the world by weight. Their length can be matched or slightly surpassed by the largest species of moray eel, but these tend to be slimmer and thus weigh less than the larger congers.