juvenile koi goldfish, popular commercial mutation aqua trade breed of wild carassius auratus carp, comet-like long tail

animal anubias aqua aquaculture aquarium auratus background breed burhead business carassius careful carp chinese clear coldwater colorful comet commercial conditions controlled cult cyprinidae decorative design ecology elegant fauna fish fishery fishkeeping freshwater goldfish growing habitat hobby instinct juvenile koi light little long low mutation nature oranda oriental ornamental plant popular precious protection sensitive shoal slow smart sociable species specimen swim tail tank threat trade underwater vulnerable water wild