One of the most popular ornamental fish that pond enthusiasts go after today is the Koi. Koi come from the common carp family, and is the Japanese word for ‘carp’. Even tho it is often thought they come from Japan, it is believed they actually originated from China and the Black, Caspian, and Aral Seas of Eastern Asia, and were introduced to Japan when the Chinese invaded the country.
Japanese farmers originally bred Koi for the sole purpose as an additional food source, but over the years, as different coloring became visible, the Japanese took the naturally occurring mutations and developed them further (another reason why it is often thought that Koi originated in Japan).
Even tho the first account we have in history of Koi being kept as a hobby dates back to AD 200, the outside world did not know about these beautiful Koi until the Great Tokyo Exhibition in 1914. Since then, Koi popularity has spread all over the world.
Today Koi are bred all over the world and are considered the most popular freshwater ornamental pond fish.