European/American Eel

Anguilla spp.

The European eel and the American eel are members of the true eel family that comprises 15 species worldwide. All of these eels are catadromous, meaning they inhabit fresh or brackish water for most of their lives but spawn in the ocean. Eels have an extraordinary life cycle. They hatch at sea, then migrate long distances back to coastal estuaries. Eventually, they travel upstream where they live for 5 to 20 years in various aquatic habitats (ponds, river basins, tidal creeks); at this time they are called yellow eels. They then metamorphose into silver eels, and when sexually mature, return to the ocean to spawn and die. Both American and European eels are thought to spawn exclusively in the Sargasso Sea, however each species returns to its respective side of the Atlantic Ocean. Consequently, American eels are native to North American watersheds on the eastern seaboard.

Full grown European and American eels can reach a length of 3 to 4 feet and can weigh 10 to 20 pounds. These eels are also considered a delicacy and as such are heavily harvested for human consumption.

Did You Know?

It is currently illegal to import any live eels into California.


Does the harvest for wildlife trade or captive breeding of this species harm wild populations?

Significant Cause for Concern

European and American eel populations are threatened by a number of factors, including over-harvesting for human consumption, diseases introduced by non-native fish, habitat destruction, and climate change. European eels are considered critically endangered—they are at a significant risk of extinction in the near future if their populations continue to decline. American eel populations are also declining; currently they are under consideration for protection under the U.S. Endangered Species Act.

So far, management and conservation actions have not been able to slow the decline of these species. Because these eels use and traverse so many habitats, they are exposed to numerous different human-related impacts. Without intervention, many eel species worldwide may go extinct in the near future. Thus, the transport and trade of these eels is regulated under international treaties.

EcoHealthy Recommendation:

Only acquire a pet that is from a reputable breeder or dealer.

Invasion Threat

Does the release or escape of this species into the wild harm the environment and/or economy?

Significant Cause for Concern

European eels have established wild populations in southern China and Taiwan. These eels are generalist predators and may carry harmful diseases so there is legitimate concern about harm to native wildlife.

American eels have been found in the waterways of California, most likely due to intentional and non-intentional releases of individuals from the food trade. These eels probably cannot reproduce in the wild (as they need to return to the Sargasso Sea to spawn), preventing their establishment. They can, however, live up to 50 years and so could impact native species for many decades. Because of this concern about escaped and/or released eels, it is currently illegal to import any live eels into California.

EcoHealthy Recommendation:

Before obtaining any non-traditional pet, check that it is legal to own one in your state of residence and check for permitting requirements. Only acquire a pet that is from a reputable breeder or dealer to ensure that you are not buying an illegally imported or wild-caught animal. Always keep your pet inside a safe and secure enclosure. Never release a pet into the wild.

Ease of Care

Does harvest, captive breeding, transport, or being kept as a pet harm individual animals?

Some Cause for Concern

Ease of care of many non-traditional pets depends on the individual owner’s years of experience and knowledge caring for a particular species. For the purposes of this website, we have geared information toward the benefit of the beginner.European and American eels are known to be skillful escape artists—they can squeeze through very small spaces such as the filter tubes in aquariums. Thus, pet owners should be sure to keep captive eels in secure enclosures.

Another important consideration is that these eels often live more than 20 (and sometimes up to 50) years in captivity and so require a long-term commitment to good pet care.

EcoHealthy Recommendation:

Before acquiring an eel, be sure to research its specific care requirements and be prepared to care for this animal for the long-term.

Health Threat

Does this animal pose a health risk to native wildlife, humans, livestock and agriculture?

Some Cause for Concern

American and European eels are known to carry many pathogens harmful to humans and other fish. The spread of parasites from introduced eels is thought to be one reason for the decline of native eel populations worldwide.

Eels are also known to be reservoirs for the pathogenic bacteria Vibrio spp. that opportunistically infect humans. This can be fatal, particularly for people with compromised immune systems or liver dysfunction.

EcoHealthy Recommendation:

Due to the potential for disease transmission to humans and other household pets, always wash your hands after handling a fish or touching the aquarium water. When purchasing a pet fish ask the seller if the fish or group of fish has a history of any health problems and for a list of any medical treatments the animal or tank has received.

EcoHealth Alliance works at the intersection of ecosystem, animal and human health through local conservation programs and develops global health solutions to emerging diseases.
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