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.
Golden trevally
The species was scientifically described for the first time by the Swedish naturalist Peter Forsskål in 1775. Forsskål referred the species to the genus "Scomber", where many jacks were placed before the recognition of the family Carangidae. The species is initially referred with two epithets; "Scomber rim, speciosus" in this publication; however the following page names it as "Scomber speciosus" with 'rim' given as a transcription of the species' Arabic name. Consequently, authorities regard "Scomber rim" as a junior synonym. Forsskål's description was based on an individual from the Red Sea off Jeddah, Saudi Arabia. The holotype has since been lost and a neotype was invalidly designated by Ronald Fricke in 1999. The specific epithet "speciosus" is Latin for beautiful. The species was transferred to "Caranx" before the Dutch ichthyologist Pieter Bleeker placed it in its own genus "Gnathanodon", with this name derived from the Latin for 'toothless jaws'. In addition to Forsskål's naming, seven other later names have been ascribed to the fish, with all of these now recognised as invalid junior synonyms under ICZN rules. The species common names generally refer to its appearance with 'golden trevally' (or kingfish), 'banded trevally' and 'king trevally' used. In Hawaii the species is referred to as the 'yellow ulua' or 'papio'.