Koi carp (Cyprinus carpio Linnaeus, 1758) are a brightly coloured fish native to Asia and Europe. They are an ornamental variant of common carp (Cyprinus carpio carpio) and were developed by selective breeding from the Asian subspecies Cyprinus carpio haematopterus. They are one of the most popular ornamental pond fish in the world – some colour variants sell for thousands of dollars (especially in Japan). In the wild, koi carp keep their colour but not the forms that command high prices overseas. Feral koi carp have become a pest fish found on every continent in the world except in Antarctica. Original public domain image from Flickr