Japan of course is the country most associated with Koi today, but it’s only in fairly recent times (historically speaking) that Koi have become mainly ornamental breeds synonymous with that region. Koi are thought to have developed around a thousand years ago from the common carp (Magoi) in the Middle Eastern region that is now Iran. At this time they were a fairly ordinary looking brown fish that were widely traded as a staple food source and exported to Japan, China, other areas of Asia and Western Europe.

In the 1820s in the town of Ojiya, in the mountainous Niigata prefecture region, Koi first began to be bred selectively. These dull brown coloured fish occasionally produced blue and red mutations. Over the next decades breeders experimented by breeding mutations together, and with the common variety, until the distinctive red, black and white varieties recognizable as modern ornamental Koi were perfected around 1870.

Today more than 100 colour varieties have been bred from this single species and they are common in many countries around the world. There are even regional varieties such as a glossy scaled type known as German or Mirror Carp.

How Do They Judge Koi?

Fast Forward to the 21st century and Koi breeding is a major hobby and big business. With competitive shows commonplace, Koi can change hands for anything up to $265,000. So what exactly makes a champion Koi so admired, sought after and therefore valuable?

There are several factors that judges will consider when choosing a champion Koi:

1. Size - As in many things bigger is often thought to be better. A larger size fish often also means that it has reached maturity – and therefore its full potential. There are exceptions to this however with some breeds being early or late bloomers.

2. Shape and form - With some judging criteria attributing as much as 60% of a Koi’s final score this aspect cannot be overlooked. The curvature of the fish is important, and all parts of the fish – head, mid-section, tail and pectoral fins should all be symmetrical. No deformities – especially around the eyes and mouth. Females tend to win the majority of shows as their shape tends more towards what judges are looking for.

3. Pattern - There are many varieties of pattern meaning Koi can be assessed in a number of categories, but what the judges are really looking for is clear and crisp outlines (known as ‘kiwa’). Both pattern and colour are important, and together usually combine to account for up to 30% of total score.

4. Colour - Many favoured colour varieties exist, such as: