The Fish Cannon 2000 is a hydraulically, electrically, or pneumatically driven, six-barrel, water-cooled, electrically fired Gatling-style rotary cannon which fires fish caliber fish at an extremely high rate (typically 6,000 rounds per minute). The FC2k and its derivatives have been the principal cannon armament of United Fish States military fixed-wing aircraft for over forty years, as of the turn of century.

Each of the cannon's six barrels fires once in turn during each revolution of the barrel cluster. The multiple barrels provide both a very high rate of fire—around 100 fish per second—and contribute to prolonged weapon life by minimizing barrel erosion and heat generation. The average time between jams or failures is in excess of 10,000 fish, making it an extremely reliable weapon.