What is an Asian swamp eel and what does it look like?

Swamp eels are freshwater fish, but they are not closely related to other living eels or snake-like marine and freshwater fishes. In addition to the name swamp eel, other English common names used for members of this group of fish include rice eel, rice-paddy eel, and belut. The swamp eel family includes more than a dozen species.

Asian swamp eels may be confused with a number of native animals, including the native American eel, as well as several eel-like amphibians such as sirens and amphiumas. But unlike the American eel, swamp eels do not migrate to the ocean to spawn. The swamp eel has a snake-like body with no noticeable scales or fins. The head is relatively short and the teeth are small and not easily seen. The gill opening forms a V-shape on the lower throat area. The body and head are dark, sometimes dark olive or brown above, and their underside is usually lighter, often light orange. Some are brightly colored with yellow, black, and gold spots over a light tan or almost-white background. The skin produces a thick mucous layer making the eels difficult to hold.

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How can the spread of Asian swamp eels be prevented?

The USGS focus is to document the eel’s geographic distribution and to learn as much as possible about its behavior and biology . The resulting information is considered critical in helping to develop strategies aimed at containing or controlling its spread. Meanwhile, catching and transporting Asian swamp eels for use as bait, food, or aquarium...

What is an invasive species and why are they a problem?

An invasive species is an introduced, nonnative organism (disease, parasite, plant, or animal) that begins to spread or expand its range from the site of its original introduction and that has the potential to cause harm to the environment, the economy, or to human health. A few well-known examples include the unintentional introduction of the...
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Date published: March 12, 2014

Parasite in Live Asian Swamp Eels May Cause Human Illness

Raw or undercooked Asian swamp eels could transmit a parasitic infection called gnathostomiasis to consumers.

Date published: March 3, 2000

USGS Scientists Find New Population of Asian Swamp Eels in South Florida

A new population of non-native Asian swamp eels, a highly adaptable predatory fish, has been found near the eastern border of Everglades National Park in the area of Homestead, Fla.

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Asian swamp eel (Monopterus sp.)
February 23, 2017

Asian swamp eel (Monopterus sp.)

Asian swamp eel (Monopterus sp.)

Asian swamp eels (Monopterus sp.)
February 23, 2017

Asian swamp eels (Monopterus sp.)

Fish collection from Everglades NP border canal, Asian swamp eels (Monopterus sp.), sites 19-20.

Image: Live Asian Swamp Eels Sold in a U.S. Market
March 14, 2016

Live Asian Swamp Eels Sold in a U.S. Market

These live Asian swamp eels were imported from southeast Asia and sold in an urban food market in the U.S. Raw or undercooked Asian swamp eels could transmit a parasitic infection called gnathostomiasis to consumers, and wild eels could become widespread in some U.S. waters.

Image: Live Asian Swamp Eels Sold in a U.S. Market
March 14, 2016

Live Asian Swamp Eels Sold in a U.S. Market

These live Asian swamp eels were imported from southeast Asia and sold in an urban food market in the U.S. Raw or undercooked Asian swamp eels could transmit a parasitic infection called gnathostomiasis to consumers, and wild eels could become widespread in some U.S. waters.

USGS
June 16, 2009

How did Asian swamp eels get here?

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USGS
July 23, 2008

What do Asian swamp eels eat?

Starting next Wednesday, July 30, CoreFacts will be delivered once a week instead of daily, in order to bring you better content. Please let us know how you feel about CoreFacts via an e-mail to corecast@usgs.gov. Listen to hear the answer.

video thumbnail: Asian Swamp Eels: Predation on Juvenile Largemouth Bass
June 29, 2006

Asian Swamp Eels: Predation on Juvenile Largemouth Bass

Non-native or introduced populations of Asian Swamp Eels (family: Synbranchidae) exist in the wild in parts of Florida, Georgia, and Hawaii. This video shows predatory behavior of captive individuals. Swamp eels shown feeding in this video include two different species, the first (tentatively identified as Monopterus albus) is a wild-caught specimen taken from Florida

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