A short and basic article on the why quality koi are costly.
 
If there is something special about Koi fish that will shock you is their worth. Koi fish are among the most expensive pet fish in the world, currently valued at approximately $2.2 million. They are members of the Carp family and resemble an overgrown goldfish. The rice farmers in Japan are associated with the raising of Koi fish since the 1700s. The farmers were striving to breed them into different patterns and colors just as we breed pets with specific traits. Koi fish breeding later became a productive activity among the Japanese, making its prices exorbitantly high. For anything to have an asking price of millions of dollars, the question you need an answer to is: why are Koi fish so expensive yet they are pets? Well, here are a few reasons to explain the cost.
 
Why Are Koi Fish So Expensive? Here's the Answer (moneyinc.com)