random header image

Texas Invasive Species Institute

Texas Invasive Species Institute

Asian Swamp Eel/ Rice Eel

Monopterus albus

Class: Actinopterygii
Order: Synbranchiformes
Family: Synbranchidae

Monopterus albus

Photographer: Haplochromis Source: commons.wikimedia.org Public Domain


Swamp eels are sometimes mistaken for the native American eel (Anguilla rostrata) or even the invasive European eel (Anguilla anguilla); but the Asian swamp eel is not even a true eel and actually belongs to the fish family Synbranchidae. Monopterus albus has a scale-less, cylindrical body with a tail that tapers are the end. The mouth contains bristle-like teeth and Monopterus albus has a distinct v-shaped gill beneath the head. Overall, the coloration is variations of green, brown and olive with the ventral side being lighter in coloration.

Ecological Threat

The Asian swamp eel is very predaceous making a threat to any new environment. However, not much is known about the effects Monopterus albus in North American waters but is has shown to be quite a problem in other countries where it is far more established. Monopterus albus has shown to displace native species and could possible accelerate the drying out of shallow waters because of the extensive burrow systems they reside in. The Everglades National Park in Florida is at high risk for being disrupted by this fish.


When individuals of Monopterus albus are born, they are all females and not until maturation do some later transform into males; this is called sequential hermaphroditism. Nocturnal in habit, Monopterus albus creates burrow systems to shelter itself during the day and eats anything from turtle eggs to frogs, shrimp and other aquatic invertebrates. Monopterus albus is able to burrow itself up to 1.5 meters deep and is capable of moving over dry land for short distances because it can breathe atmospheric oxygen for brief periods of time.


Introduction has been a result of the aquarium trade, releasing from fish markets, stocking as a food source or escaped from fish farms during flooding events. With this species being nocturnal in habitat it is not seen often by humans, so it may be more established in the United States than what is known. Known for being a food source in Asia and Japan, this species was introduced by Asian immigrants to Oahu, Hawaii before 1900. Introduction to the continental United States in Georgia occurred in 1994 and was probably from aquarium releasing. Since the late 1990s the Asian swamp eel has become established in Florida and in 2008 it was found in Silver Lake in New Jersey.

Native Origin

Asia; from India to China

Current Location

U.S. Habitat: A wide variety of freshwater habitats are preferred, such as:  shallow wetlands, stagnant mashes, rivers or even ditches. Also, the Asian swamp eel does have a salinity tolerance so they can be found in brackish and saline waters.


U.S. Present: FL, GA, HI and NJ


The Asian swamp eel has been used within the aquarium/fish trade and fish markets in the United States. Some studies are testing the use of electrical barriers and vegetation removal, in waters where Monopterus albus is present. Trapping by electroshocking helps limits this species’ distribution; but what can be done by anyone is to not purchase this fish from any pet store and to report sightings to any state or federal invasive species entity.


Hill, J.E. and C.A. Watson. 2007. Diet of the nonindigenous swamp eel in tropical ornamental aquaculture ponds in West-Central Florida. North American Journal of Aquaculture 69:139–146

Maciolek, J. A. 1984. Exotic fishes in Hawaii and other islands of Oceania. Pages 131-161 in
Distribution, Biology, and Management of Exotic Fishes The Johns Hopkins University Press.

Shafland, P.L., K.B. Gestring, and M.S. Sanford. 2010. An assessment of the Asian swamp eel (Monopterus albus) in Florida.  Reviews in Fisheries Science 18(1):25-39.

Woodward, Susan L., and Joyce Ann. Quinn. "Asian Swamp Eel." Encyclopedia of Invasive Species: From Africanized Honey Bees to Zebra Mussels. Santa Barbara, CA: Greenwood, 2011. 160-62. Print.  

Internet References



http://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=974 (non-indigenous Aquatic Species)

< Back to Inventory