See the Top 5 Largest Eels You Might Encounter in U.S. Waters

With around 800 total species covering more than 100 genera, eels are a surprisingly diverse and eclectic group of fish! They range in size from as little as two inches to more than 10 feet in length, and some eels can weigh more than 200 pounds. But what are the largest eels in the United States’ waters? Read on to learn all about the top five below!

5. American Eel (Anguilla rostrata) – Up to 4 feet long, 15 lbs.

While North America has lots of marine eels along its coastlines, only one species is truly freshwater-dwelling: the aptly-named American eel! Although its long, gray body is covered in tiny scales, the mucus layer its skin secretes gives it a smooth appearance. 

As one of the United States’ largest eel species, the American eel is capable of reaching up to four feet long. However, it more commonly reaches lengths of around two to three feet. It’s also fairly heavy despite its long, slender body–it can weigh up to 17 pounds! Notably, the species is sexually dimorphic, with females being larger and lighter in color but also having smaller eyes and fins located higher up on the body.

American eels can be found throughout North America’s freshwater habitats. They are quite hardy and can live in streams, rivers, and lakes, particularly those with lots of muddy substrate and vegetation. Despite generally being freshwater fish, they sometimes migrate between brackish, fresh, and even saltwater habitats. They mainly feed on small fish, worms, mollusks, and even insects they find buried in the substrate. Though their eyes are well-developed, American eels rely mainly on their sense of smell to navigate and find food.

4. California Moray Eel (Gymnothorax mordax) – Up to 5 feet long, 15+ lbs.

Now that we’ve covered the United States’ only freshwater species, we can move on to its largest marine eels! The fourth-largest eel species in America is the California moray, one of around 200 unique species of moray eels. Interestingly, this species is the only moray eel dwelling off of California’s coasts. Its geographic range is pretty limited for an eel, being restricted mainly to the eastern Pacific Ocean along southern California and Baja California’s coastlines.

Like most moray eels, the California moray is large, with a long and heavy body. It can reach lengths exceeding five feet and weigh up to 15 pounds! Its snake-like body has no pelvic fins or pectoral fins. 

Notably, this species also lacks gill covers and mainly uses its mouth to breathe by pumping water into two small openings on the sides of its head. Its body can range in color from light brown to dark green, and its eyes are small in comparison to its head size. 

Its large, cavernous mouth is equipped with a set of large pharyngeal jaws in the back of the throat, which it uses to move prey it swallows from its mouth down towards its stomach. Finally, a set of teeth in the roof of its mouth can depress and fold upward to further aid in swallowing prey like fish and other aquatic invertebrates.

The California eel’s preferred habitats along California’s coasts are large, rocky coral reefs. While juveniles of the species mainly live in shallow tide pools, the adults prefer deeper waters. They are apex predators within this habitat and are nocturnal in nature, mainly hunting at night. They can even eat prey as large as octopuses and other moray eels!

3. Green Moray Eel (Gymnothorax funebris) – Up to 8.2 feet long, 65+ lbs.

The United States’ next-largest eel species is the Green moray, one of the largest morays and the largest type of moray in the Atlantic Ocean. It lives all along the eastern United States’ coast, from as far north as Long Island, New York all the way down to Brazil’s eastern coastline. Although the green moray appears to be a bright yellowish-green in color, its true body color is more of a dark brown. This is due to a protective mucus it constantly secretes from its skin using specialized cells.

Like most other moray eels, the green moray is large and long with a bulky, muscular body. When fully mature, it can reach lengths exceeding eight feet and weigh more than 60 pounds! The largest specimen ever recorded weighed 65 pounds and measured 8.2 feet. 

Also similar to other moray eels, the green moray’s body lacks pectoral and pelvic fins entirely. Its single dorsal fin extends down the length of its neck and back before connecting to its tail fin. Furthermore, its body is laterally compressed, meaning it has a somewhat flattened appearance. 

Though its small eyes are well-developed, the green moray eel’s eyesight is fairly poor. Instead, it relies on its strong sense of smell to navigate and locate prey. A notoriously elusive species, it is a nocturnal hunter that mainly feeds on all types of fish as well as crustaceans and cephalopods like octopuses and squid.

2. Giant Moray Eel (Gymnothorax javanicus) – Up to 9.8 feet long, 66 lbs.

The United States’ second-largest eel is also a moray species. It’s the giant moray, which is also one of the largest eels on the planet. Their massive bodies can reach almost ten feet long, and they can weigh more than 65 pounds! Though it’s technically the largest moray species overall, the closely-related slender giant moray actually exceeds it slightly in total body length.

The giant moray eel’s body is dark brown in color with tiny black spots around the head and neck. As juveniles, giant morays appear lighter in color with large dark brown splotches. But as they age, these splotches become small, mottled spots that darken in color. Like other morays, it lacks pelvic and pectoral fins. Instead, its laterally compressed body has a single dorsal fin that extends down the length of the back before fusing with its smaller caudal and anal fins.

Giant moray eels have a wide geographic range. They live throughout the Indo-Pacific region, including parts of the Red Sea. Though they don’t occupy much of the continental United States’ waters, they do live along the Hawaiian Islands’ shores. They mainly occupy coastal lagoons and coral reefs, where they hide amongst the coral waiting to strike prey like fish and marine invertebrates. 

Bizarrely, the giant moray eel seems to engage in cooperative hunts with the roving coral grouper fish. While the two live in the same general habitat, the grouper occupies slightly shallower waters. When giant morays hunt prey within the coral reefs they inhabit, the prey will flee out of the reefs and up towards the grouper’s range. Conversely, when the grouper hunts its prey, it will similarly scare them into fleeing back into the reefs, allowing them to be eaten by giant morays.

1. American Conger (Conger oceanicus) – Up to 7 feet long, 80 lbs.

The largest species of eel in the United States isn’t a moray–it’s actually the American conger, a downright massive marine eel that can reach almost seven feet long and weigh more than 80 pounds! While many moray species can be slightly longer, the American conger can reach a much heavier weight. To be exact, the maximum recorded length for the species is 6.6 feet, while the heaviest specimen weighed a whopping 88 pounds. Specimens this large are somewhat rare, however, as most mature individuals measure around 3 feet in length.

The American conger has a long, cylindrically-shaped body with a prominent, protruding upper jaw. Unlike moray eels, this species has pectoral fins. Its single dorsal fin begins just behind the pectoral fins and extends down the length of the back before fusing with its anal fin. Its overall body color ranges from brownish-gray to a more uniform light gray. 

Notably, the American conger eel has a fairly wide geographic range within the western Atlantic Ocean. A hardy and adaptable species, it can be found as far north as Cape Cod and as far south as the Gulf of Mexico. Like most eels, it is nocturnal in nature and prefers to hunt its prey at night. It feeds on all types of fish, as well as small-to-medium-sized crustaceans and mollusks.

Summary of the United States’ Largest Eels

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