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 guitarfish
The common guitarfish lives close to the coast and breeds in shallow water. This makes it vulnerable, and it is fished, primarily as bycatch, over much of its range. In the northern Mediterranean, catches used to be landed, along with the blackchin guitarfish ("Rhinobatos cemiculus"), at fishing ports such as Palermo, but both fish are now no longer seen there and have probably been extirpated from the area. It is no longer to be seen in the Balearic Islands either. Off the coasts of West Africa, it is caught as bycatch by international shrimp trawling vessels, and by cephalopod fisheries trawling the seabed, as well as being caught by local artisanal gill net fishermen. Its meat may be salted and exported and its fins sold to Asia. It may be safest in the southern Mediterranean where the fishing is less intensive and it is still sometimes landed, but even there, most of the fish landed are immature. For the fish to have a long-term future and the fisheries to be sustainable, the adult fish need to be allowed to mature and breed. There is no special conservation plan for this fish and the International Union for Conservation of Nature has assessed its conservation status as being "endangered".