Description: Introduced to the United States in the 1800s as an ornamental fish. Introductions from intentional releases of goldfish have been reported in every U.S. state except for Alaska.
Identification: Gray-green above with a brassy sheen on back and sides; white to yellow below and gray to brown dorsal and caudal fins. Large scales, long dorsal fin, and a stout, sawtoothed spine at the front of the dorsal and anal fins. Body stout and thick-set, with a thick and short caudal peduncle. Pharyngeal teeth. Average size is 4.6 to 8.6 inches, grow up to 16 inches.
Habitat: Native to eastern Asia. Prefers shallow, muddy pools or backwaters or slow rivers, ponds and lakes. Usually prefer warm turbid or vegetated waters. Tolerant to temperature fluctuations and turbidity; also tend to be more tolerant of some forms of pollution than other fishes.
Reproduction: Goldfish spawn in shallow waters among weeds, releasing up to several hundred thousand eggs. Females spawn multiple times during the spawning period. The eggs take about a week to hatch; the young later attach themselves to aquatic plants while the yolk sac is absorbed.
Impact and Damage: Goldfish have the potential to crowd out native fish populations and compete with them for food.
Similar species: Common carp (Cyprinus carpio), which can be distinguished by their lake of two small barbels near each corner of the mouth.
Monitoring and rapid response: Many states have regulations prohibiting the release of goldfish into the environment and their use as bait.
Credits: The information contained in this factsheet was provided by the Shedd Aquarium and the Global Invasive Species Database.
Individual species images that appear with a number in a black box are courtesy of the Bugwood.org network (http://www.invasive.org).Individual photo author credits may not be included due to the small display size of the images and subsequent difficulty of reading the provided text. All other images appear courtesy of Google (http://images.google.com).