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 yabby
The common yabby ("Cherax destructor") is an Australian freshwater crustacean in the Parastacidae family. It is listed as a vulnerable species of crayfish by the World Conservation Union (IUCN), though the validity of this listing is questionable; wild yabby populations remain strong, and have expanded into new habitats created by reservoirs and farm dams.