How Big Do Eels Get in Freshwater Lakes?

Eels are mysterious, snake-like fish that have fascinated anglers, scientists, and storytellers for centuries. Their slippery bodies and nocturnal habits often leave them hidden from view, but when one surfaces in a net or on a fishing line, the first question is usually the same: how big do these things actually get in freshwater lakes?

Common Freshwater Eel Species

In North America, the most familiar freshwater eel is the American eel (Anguilla rostrata). It ranges throughout the eastern United States and Canada, inhabiting rivers, ponds, and large lakes before eventually migrating thousands of miles to the Sargasso Sea to spawn. Across Europe and Asia, the European eel (Anguilla anguilla) and the Japanese eel (Anguilla japonica) serve similar ecological roles.

These eels are not permanent lake residents in the sense of breeding there, but they can spend decades living in freshwater before making their final ocean journey.

Average Size in Lakes

Most eels caught in freshwater lakes are between 1 and 3 feet long, weighing anywhere from 2 to 5 pounds. At this size, they are powerful enough to put up a fight on light tackle and can startle anyone who mistakes them for a water snake in the shallows.

Record-Breaking Giants

While the average eel is modest in size, some grow much larger:

• American eel: Can reach lengths of 4 to 5 feet and weigh 10 to 15 pounds, though specimens this size are rare.

• European eel: Known to exceed 4 feet and sometimes reported at over 20 pounds.

• Japanese eel: Typically smaller but can still surpass 3 feet in length.

There are persistent lake legends of eels growing to monstrous proportions, with old tales describing “serpents” pulled from nets or spotted in deep, murky waters. While most of these stories are exaggerated, they stem from the fact that eels can live for decades—some documented cases show individuals living over 50 years—giving them a long window to grow unusually large.

In Massachusetts, there are a few records worth noting. According to the Massachusetts Division of Fisheries and Wildlife, the largest eel on record in the state weighed 9 pounds and measured 41 inches long. That’s nearly the size of a keeper striped bass!

Stories from old-timers suggest that eels even larger than this have been pulled from secluded lakes or accidentally caught in commercial gear, though many of these tales remain unverified.

Why They Can Get So Big

Eels are opportunistic feeders, consuming everything from insects and worms to fish and crustaceans. In large freshwater lakes with plentiful food and few predators, they thrive. Combined with their slow metabolism and long lifespan, these factors allow eels to grow far beyond the average fish of the same habitat.

The Mystery Continues

Even today, much about freshwater eels remains mysterious, especially their growth potential. While science has pinned down their migration and life cycle, there’s still room for myth and wonder when an angler hauls up a long, writhing specimen from the deep.

So, the next time you’re fishing a lake at night and feel a powerful tug on the line, don’t be surprised if it’s an eel—and keep in mind that it might be bigger than you think.