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.
Common ling
The common ling ("Molva molva"), also known as the white ling or simply the ling, is a large member of the family Lotidae, a group of cod-like fishes. It resembles the related rocklings but it is much larger and has a single barbel. It is found in the northern Atlantic, mainly off Europe, and into the Mediterranean Basin and it is an important quarry species for fisheries, especially in the north eastern Atlantic, although there are some doubts as the sustainability of the fisheries. As an edible species it is eaten fresh, frozen or dried but also preserved in lye, while the roe is a delicacy in Spain.