Monopterus albus - Asian Swamp Eel


Information Last Reviewed Spring 2007


Significant adverse impacts have yet to be documented, but due to their predatory nature, Asian swamp eels appear to have the potential for adverse environmental impacts in North America. There is concern, for example, that they may disrupt the Everglades National Park ecosystem.




General Biology

Life Cycle

Habitat Characteristics





Web Sites







Phylum Chordata

Class Actinopterygii

Order Synbranchiformes

Family Synbranchidae






Swamp eels are not true eels (order Anguilliformes). True eels have scales, dorsal, anal and caudal fins, and functioning pectoral fins. True eels have two gill openings and the gill membranes are not united. An obvious difference between the two groups is that anguilliform eels have distinctive, planktonic larvae that are thin, transparent, and can be quite large and leaf-like in appearance. As such, the Anguilliformes is a group of fish with largely ancestral characteristics and placed in the teleost infradivision Elopomorpha. Swamp eels have mostly derived characteristics and are placed in the infradivision Eutelostei and are percomorphs.


Distinguishing Characteristics







General Biology:





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Life Cycle:


The life cycle of the Asian swamp eel takes place solely in freshwater.










Habitat Characteristics:


Preferred Environment












Native Range


North American Distribution




Probable Means of Introduction






Although the ecological impacts in North American waters are relatively unknown, the following impacts are documented in other regions of the world where they have become established:










Control Measures




Prevention Techniques






Devick, W. S. 1991. Disturbances and Fluctuations in the Wahiawa Reservoir Ecosystem. Project F-14-R-15, Job 4, Study I. Division of Aquatic Resources, Hawaii Department of Land and Natural Resources. 21 pp.


Devick, W. S. 1991. Patterns of introductions of aquatic organisms to Hawaiian freshwater habitats. Pages 189-213 in New Directions in Research, Management and Conservation of Hawaiian Freshwater Stream Ecosystems. Proceedings of the 1990 Symposium on Freshwater Stream Biology and Fisheries Management. Division of Aquatic Resources, Hawaii Department of Land and Natural Resources.


Johnson, D. S. 1967. Distributional patterns of Malayan freshwater fish. Ecology 48(5):722-730.


Kottelat, M., Whitten, A. J., Kartikasari, S. N., and Wirjoatmodjo, S. 1993. Freshwater Fishes of Western Indonesia and Sulawesi. Periplus Editions, Ltd., Republic of Indonesia. 221 pp. (+ plates).


Lake, J. S. 1971. Freshwater Fishes and Rivers of Australia. Sydney, Australia. 61 pp.


Liem, K. F. 1981. Larvae of air-breathing fishes as countercurrent flow devices in hypoxic environments. Science 211:1177-1178.


Liem, K. F. 1987. Functional design of the air ventilation apparatus and overland excursions by teleosts. Fieldiana: Zoology 37:1-29.


Maciolek, J. A. 1984. Exotic fishes in Hawaii and other islands of Oceania. Pages 131-161 in Distribution, Biology, and Management of Exotic Fishes (Courtenay, Jr., W. R. and Stauffer, Jr., J. R., eds.). The Johns Hopkins University Press, Baltimore, Maryland.


Merrick, J. R. and Schmida, G. E. 1984. Australian Freshwater Fishes: Biology and Management. Griffin Press, Netley, South Australia.


Smith, H. M. 1945. The fresh-water fishes of Siam, or Thailand. Bulletin of the United States National Museum (Smithsonian Institution) Issue 188. 622 pp.




Web Sites:

Sherpa Guide to the Asian Swamp Eel

United States Geological Survey Nonindigenous Aquatic Species

United States Geological Survey Press Release


This report was prepared by Danielle M. Crosier and Daniel P. Molloy (New York State Museum) with assistance from Robert A. Daniels (New York State Museum).