The Goldfish is one of the first invasive species to reach North America. Originating in eastern Asia, it was first kept as a pet in China and has since been sold around the world for use in aquariums, ponds and water gardens. It was brought to North America in the 1600s and was established in New York ponds by 1842.
Found wild in quiet areas of ponds, streams and pools in urban and suburban areas across Ontario, Goldfish are able to tolerate fluctuations in water temperature and oxygen levels. Goldfish do not compete well with some native species in healthy ecosystems, but in degraded conditions it may threaten some native species due to its tolerance of poor water quality. Goldfish typically live for 6 to 7 years, although it can live as long as 30 years and grow up to 40 cm in length and 3 kg in weight. Goldfish are closely related to the Common Carp (Cyprinus carpio), which it has hybridized with leading to complex crosses of the two species.
Control methods include physical removal in small and shallow water bodies and lowering of water levels or draining of water in ponds.
Introduced around the world, Goldfish are established in all the Canadian provinces and all the American states, except for Alaska. Ontario has established populations on the north shore of Lake Erie, the west end of Lake Ontario and in other water bodies across the province.
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