The Maryland Department of Natural Resources says the scary northern snakehead fish have made their way into the Chesapeake and Ohio Canal, and almost certainly the upper Potomac River.
Wildlife officials are urging people to catch and kill the predatory fish.
Snakeheads are native to China, Korea and Russia.
They can breathe air, survive on land and adapt and thrive in foreign environments.
The agency says anglers reported catching snakeheads last fall.
Northern snakeheads appeared in the tidal Potomac watershed in 2002. They are now firmly established in the Patuxent River, and have spread to other tidal waters in Maryland and Virginia.
See THOSE LURKING, HORRIFIC SNAKEHEADS | 
