In memory of the koi pond in the garden that I played in as a child at my grandparents' place. There is a lot of tradition behind koi classification and collection. Koi can live an average of 30-35 years and the largest of koi can be quite expensive. The kohaku is the most common of koi variety, and the HI is counted by "steps". Another popular variety is the sanke koi, with fairly specific amount and placement of the black, red, and white colors. My favorite is the kumonryu. "Ryu" in Japanese means dragon, and who doesn't love a fish with the word "dragon" in their name? The name aside, kumonryu have a gorgeous pattern.