Ornamental fish refers to fish with bright colors or peculiar shapes of ornamental value. They are distributed around the world and species no less than thousands. Some live in fresh water, some in sea water, some from temperate regions, and some from tropical regions. Some are famous for their gorgeous colors, some for their strange shapes, and some for their rarity and preciousness. In the world ornamental fish market, it is usually composed of three strains: temperate freshwater ornamental fish, tropical freshwater ornamental fish and tropical seawater ornamental fish.