Florida: An established (reproducing) population of bullseye snakehead was found in Broward County in 2001. This is the largest snakehead species. It commonly grows to a length of four feet. This species may have been introduced intentionally as a food fish, released by aquarium hobbyists or escaped from a fish farm - although there are no fish farms in the immediate area. Two northern snakeheads have been caught in the St. Johns River in Seminole and Volusia counties. This species was probably released as a food fish.
California: California Fish and Game personnel collected a snakehead in Silverwood Lake in the San Bernardino Mountains
east of Los Angeles in 1997.
Hawaii: The chevron snakehead was established on the island of Oahu in the late 1800s, where it is cultured as a food fish.
Maryland: Two adult and about 100 juvenile northern snakeheads were discovered in Crofton, Maryland in late June and early July 2002. The species came from live food markets.
New England States: A northern snakehead was collected in October 2001 from Newton Pond in Sudbury, Massachusetts. The likely source of this fish was the live fish market. Specimens of the giant snakehead have been collected from open waters in Maine, Massachusetts and Rhode Island. These snakeheads likely were released by aquarium owners whose "pets" grew too large or too expensive to feed. The giant is the most predacious snakehead species and has been known to attack humans.