Exactly how much Koi fish cost depends on a number of factors, including the size and the specific breed of the fish. As of June 2014, a small, standard Koi fish costs as little as $4. Koi that are larger in size can cost up to $3,000.
Koi fish can be purchased through a number of reputable dealers; however, they are often not eligible for return or a refund. A reputable dealer will ensure that the fish arrive alive but generally cannot accommodate for a refund if the fish dies. This is because it can be difficult to verify the cause of death, and Koi fish may jump out of a new environment if not monitored.