Life Span of Koi: 60+ Years
Great info from Ozarkkoi!
Determining the age of a koi fish, also known as nishikigoi, is not an easy task. Some signs to take into consideration are the variety, coloration, appearance and size of the koi fish in question.Lastly, the size of your koi fish will help determine its age. Mature nishikigoi can reach 36″ or more in length. If your koi fish is considerably smaller, it is younger in age or its growth has been stunted.
