What is the smallest koi?

The smallest koi is typically the "Kohaku" variety, which can be bred to be miniature or "pond" koi. These smaller koi can reach lengths of about 6 to 12 inches, depending on their genetics and environment. However, some specially bred varieties, like the "Dwarf" koi, can be even smaller. Overall, koi sizes vary significantly, but these smaller types are often sought after for home aquariums and smaller ponds.