Japanese Koi are ornamental fish, subspecies of the common carp, and the Japanese name for koi fish – Nishikigoi – actually means brocaded carp. This sub-species of fish were selectively bred for eye-catching patterns and vibrant colors, and considered to be a symbol of good luck and prosperity. They best thrive in good sized ponds with plenty of cover and an efficient filtering system. As koi are cold water fish, specific pond construction to accommodate their habitat needs is required. Feed commercial flake or pellet food, supplemented with fruit, vegetables, shrimp and tubifex worms.