A snakehead caught in the Potomac River is marked by a tagging gun. These tags tell the public they are to destroy the fish if caught. There is also a number people can call to provide information about the fish. (Barbara L. Salisbury/The Washington Times)

A snakehead caught in the Potomac River is marked by a tagging gun. These tags tell the public they are to destroy the fish if caught. There is also a number people can call to provide information about the fish. (Barbara L. Salisbury/The Washington Times)