Practical information to identify and manage non-native, invasive plants and animals
The Quiet Invasion:
A Guide to Invasive Species of the Galveston Bay Area
Asian swamp eel
Monopterus albus

ITIS TSN:166697
Presence:Species of Concern
Habitat:Aquatic
Native Range:Asia
Human Health
This species poses no known human health impacts.
Prohibited Lists
This species (and all other eel species from the family Synbranchidae) are legally classified in Texas as exotic, harmful, or potentially harmful. No person may import, possess, sell, or place this species into state waters except as authorized by a rule or permit issued by the TPWD. A person may possess exotic harmful or potentially harmful fish (exclusive of grass carp) without a permit only if the fish have been gutted.
Introduction Pathways
The Asian swamp eel was originally introduced to Hawaii in the 1800s as a food source and in Southeast Florida in the mid to late 1980s or early 1990s (Shafland et al. 2010). Live eels have been sold through the aquarium trade and live seafood markets. This species has also been farmed in some areas. Asian swamp eel in the U.S. may actually represent a species complex, rather than a single species (Rosen and Greenwood 1976; Shafland et al. 2010).
Geographic Distribution
As of 2010, Asian swamp eel is not reported in Texas. This species is reported in Hawaii, Florida, Georgia, and New Jersey (USGS 2010b).
Specific Primary Habitats
M. albus can be found in ponds, canals, and rice fields where it burrows in soft sediments or hides in crevices (Bricking 2002; ISSG 2005c; Shafland et al. 2010). The Asian swamp eel is primarily nocturnal. This air-breathing species can live in waters with low dissolved oxygen concentrations. This species can survive water temperatures as low as 8°C (46°F) (Shafland et al. 2010).
Ecological, Economic, or Social Impact
Where found, this species alters food web dynamics. Early accounts described this species as a voracious predator. However, more recent studies indicate that the swamp eel is an opportunistic predator (Freeman and Burgess 2000; Hill and Watson 2007; Shafland et al. 2010). Native species of fish and birds have also been observed feeding on Asian swamp eel.
Physical Description
This species of fish can grow to be 1 meter in length. It is snake-like in appearance and does not possess scales. Most are dark, olive-brown in color, but lighter, spotted, and brightly colored variations have been documented. Larger specimens have an overhanging upper jaw. Eyes are small in size and are covered by a thin layer of skin.
Reproduction Characteristics
Asian swamp eels begin their life as females with some individuals transitioning to males as they mature (Shafland et al. 2010). Shafland et al. (2010) found that ripe females have more than 400 eggs on average. Matsumoto et al. (2010) found that reproductive strategies differ throughout the species native range with some geographic populations exhibiting parental care (nest digging, production of foam mass to protect eggs and mouth brooding) while other lay eggs at floating roots of water hyacinth (with no parental care).
Feeding
This opportunistic predator has been found to feed on Prey items include amphipods, crayfish, fish, fish eggs, insects, and Oligochaetes (Hill and Watson 2007; Shafland et al. 2010). Shafland et al. (2010) also found specimens that had fed on a small turtle and the head of a snake.
Control
Since early detection is key to preventing the spread and establishment of this species, regional/local monitoring or surveillance is essential. Nonnative species of eels should not be imported or released in local waterways. If found in local waters, note the capture location, kill and freeze the fish, and notify the TPWD.

This species belongs to the following lists:
Images
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Adult Asian swamp eel (<i>M. albus</i>). Photo courtesy of Paul Shafland, Florida Fish and Wildlife Conservation Commission, USGS NAS Database, http://nas.er.usgs.gov.
Adult Asian swamp eel (M. albus). Photo courtesy of Paul Shafland, Florida Fish and Wildlife Conservation Commission, USGS NAS Database, http://nas.er.usgs.gov.
Asian swamp eel (<i>M. albus</i>). Photo courtesy of USGS, URL: fl.biology.usgs.gov.
Asian swamp eel (M. albus). Photo courtesy of USGS, URL: fl.biology.usgs.gov.
Asian swamp eel (<i>M. albus</i>). Photo courtesy of USGS, URL: fl.biology.usgs.gov.
Asian swamp eel (M. albus). Photo courtesy of USGS, URL: fl.biology.usgs.gov.
Page Updated/Reviewed: 08/31/2010 1:54 PM
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