The Northern Snakehead (Channa argus) is a large (to 850 mm) predatory freshwater fish native to Asia, from the Amur River to Hainan Island. It has been introduced to the Arla Sea basin in Uzbekistan, and more recently to several regions in the United States. There have been scattered introductions in many states and established populations in the Chesapeake Bay, Delaware River, lower Hudson, and Arkansas River basins. The Northern Snakehead was first caught in a pond in Crofton, Maryland, in 2002 and then quickly eradicated. However in 2004, an established population of Snakeheads was found in the Potomac River and became widely established in Chesapeake Bay tributaries. Northern Snakeheads are tolerant of a wide range of temperature (0-35° C), brackish water (to 15 PSU) and are obligate air-breathers. This fish is a valued food-fish in Asia, and has developed a sport-fishery in the Chesapeake Bay, involving bow-hunting. They are a predator on gamefishes such as Largemouth Bass, and could have impacts on wetland food-webs.