Japanese Koi (By Age) are grouped to reflect their stage of development, from small, fast-growing Tosai through to large, more refined adults like Sansai and Yonsai. Buying by age gives you a clearer idea of each fish’s growth potential, body shape development and how stable its pattern and colour are likely to be. Younger koi are ideal if you enjoy watching them grow and change, while older fish offer more finished body conformation and established markings. Whatever stage you choose, each age class has its own charm and is selected to perform well in a well-filtered, well-maintained koi pond.
