American Eel

Anguilla rostrata

Copyright, Garold Sneegas

American Eels are long, narrow, snake-like fish. They can grow to almost five feet long.

The color of these eels depends on their age and habitat. Older eels are usually dark brown or greenish, with yellowish-white bellies. Their color can change from light to dark within a few hours. This helps them blend in with their surroundings.

The scales of these fish are embedded in the skin, which is covered with a thick mucus coating. American Eels have large heads.

American Eels are unique because they are one of the few fish that are catadromous. This means they spend most of their lives in fresh water, but return to the sea to breed.

Copyright, Doug Stamm/ProPhoto 

Copyright, Garold Sneegas

The American Eel's life cycle starts as an egg in the Sargasso Sea near the Bahamas. Tiny larvae, called "glass eels," hatch and drift in ocean currents. Glass eels are very thin, like ribbons, and they are transparent. It takes almost a year before these tiny eel larvae reach the coast of the United States. Many glass eels are eaten by predators before they ever reach fresh water.

When glass eels reach the coast, they metamorphosize (change) into a new body shape. These rounder, darker eels are now called "elvers."

Elvers are about 3 inches long when they enter fresh water in the spring. Most elvers swim upstream into rivers and smaller streams. Some stay in bays and mouths of rivers where the water is brackish (part salt/part fresh).

Elvers continue to grow as they swim upstream. It will be at least three years before they mature into adulthood and are ready to return to the sea to mate. Many eels live up to 20 years in fresh water before they return. American Eels always go back to the Sargasso Sea to mate.

Northeast Eel and Elver Company

Copyright, Tim Watts

Copyright, Garold Sneegas

As American Eels move upstream, they often have to navigate around obstacles. Eels can climb over rocks, dams, and even waterfalls.

They have the ability to absorb oxygen throught their skins to breathe. This allows them to survive out of water for several hours. If an eel is found doing this, it is most often on a damp, rainy night.

Eels can also travel by underground waterways. This explains how eels are found in ponds that don't have a stream leading to it.

American Eels are mostly nocturnal. They lay buried in mud or gravel during the day. They also hide under logs or boulders, below undercut banks, or in dense vegetation (water plants). Eels prefer quiet, slow-moving water with muddy bottoms.

American Eels are not picky eaters. Foods include: small fish, shrimps, crayfish, aquatic insect larve, snails, mussels, aquatic worms, and amphibians (frogs, toads, salamanders). Eels will also eat animals that fall into the water, such as terrestrial insects and earthworms. They are carrion-eaters as well, meaning they eat dead animal matter.

Predators of eels include larger fish, gulls, and eagles.

Copyright, Garold Sneegas

American Eels can live a long time. One specimen, captured as an elver, lived in an aquarium for 85 years.

Additional Media


American Eel Video #1 (Small) (Large)

Video (Long download, approx 1 minute on T1)
Mark Moran

American Eel Video #2 (Small) (Large)

Video (Long download, approx 1 minute on T1)
Mark Moran

American Eel Video #3 (Small) (Large)

Video (Long download, approx 1 minute on T1)
Mark Moran

American Eel Video #4 (Small) (Large)

Video (Long download, approx 1 minute on T1)
Mark Moran

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Relationship to Humans:

American Eels are eaten by many people, especially in Europe and Asia. Because of this, elvers are captured and exported to other countries. Recently, scientists are becoming concerned that "over-fishing" of eels may be impacting them in a negative way. American Eels are helpful because they control insect and fish populations. They also eat dead animal matter and other stinky things that other animals won't eat. This helps waterways stay clean and healthy. American Eels are basically harmless, but large ones will bite if handled.


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Anguilla rostrata


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