Koi
The major named varieties include:Goldfish (金魚) were developed in China more than a thousand years ago by selectively breeding Prussian carp for color mutations. By the Song dynasty (960–1279), yellow, orange, white, and red-and-white colorations had been developed. Goldfish ("Carassius auratus") and Prussian carp ("Carassius gibelio") are now considered different species. Goldfish were introduced to Japan in the 16th century and to Europe in the 17th century. Koi, though, were developed from common carp in Japan in the 1820s. Koi are domesticated common carp ("Cyprinus carpio") that are selected or culled for color; they are not a different species, but a subspecies, and will revert to the original coloration within a few generations if allowed to breed freely.
Dissostichus
Dissostichus, the toothfish, is a genus of notothen found in the Southern Hemisphere. Toothfishes are marketed in the United States as Chilean sea bass (or Chilean seabass) or less frequently as white cod. "Chilean sea bass" is a marketing name, coined in 1977 by Lee Lantz, a fish wholesaler who wanted a more attractive name for selling the Patagonian toothfish to Americans. In 1994, the U.S. Food and Drug Administration (FDA) accepted "Chilean sea bass" as an "alternative market name" for Patagonian toothfish. The toothfish was remarkably successful in the United States, Europe and Asia, and earned the nickname “white gold” within the market.Toothfishes are vital to the ecological structure of Southern Ocean ecosystems. For this reason, on 4 September a national day is dedicated to the toothfish in South Georgia.