The behaviour of eels in fresh water extends the air of
mystery surrounding them. They move freely into muddy, silty
bottoms of lakes, lying buried in the daylight hours in summer.
[...] Eels are voracious carnivores, feeding mainly at
night and consuming a wide variety of fishes and invertebrate
creatures. Contrary to earlier thinking, eels seek living
rather than dead creatures and are not habitual eaters of
carrion.
[ Freshwater Fishes of Canada, by Scott and Crossman ]