koi or more specifically jinli or nishikigoi are colored varieties of amur carp cyprinus rubrofuscus that are kept for

amur animal aquatic are asia asian black bright carp color colored colorful cooking culture cyprinus decorative exotic fancy fish food freedom garden gold golden goldfish japan japanese jinli kept koi lake life more natural nature nishikigoi ocean orange ornamental outdoor oxygen peaceful pet pond ponds pool pretty purposes red rubrofuscus sea seafood specifically swim that traditional tropical varieties water yellow