The Northern Snakehead is native to China, Russia, North and South Korea. They have no natural enemies, and they could decimate populations of native fish. It can live in temperatures ranging from 0-30 degrees Celsius, it is found in muddy or vegetated ponds, swamps, or slow moving streams. They can survive for up to 4 days out of the water and they can travel from one body of water to another by wriggling their bodies over the ground. It is able to survive in much of North America should it become established. The Northern Snakehead preys on other fish, 90% of its diet consists of other fish though they still eat crustaceans, insects and plants. In 2002, the Northern Snakehead was found in Crofton, Maryland, officials posted signs encouraging anglers to kill any snakehead that they caught. Reproducing populations of snakeheads have now been discovered in Maryland, California, and Florida. Individual fish have also been caught in Maine, Massachusetts, Rhode Island and Hawaii. In October, the U.S. Fish and Wildlife Service added snakeheads to the list of injurious species. This listing essentially stopped the importation and interstate transport of all 28 snakehead species in the U.S., a move that has probably prevented thousands of shipments of snakeheads from entering the country. This move was under consideration before the discovery of the Maryland fish.
http://www.csa.com/discoveryguides/snakehead/overview.php
