The Value of Koi - Part 2

Evaluation criteria

The following extract from Japanese Ornamental Koi Carp: Origin, Variation and Genetics may shed more light on the issue of quality and consequently price of nishikigoi:

Because koi is an ornamental fish, its value is affected by perceived qualities and breeders aim to improve those qualities through parentage and selection criteria. While color and color pattern play a part in determining the value and marketability of mass produced, commercial fish, those are not prime factorsin determining the value of individual, high quality fish from well-known producers. These breeders created lines that have shown consistent, predictable and sought after qualities. Great value is attached to such a lineage. The essential elements determining the value of fish that breeders try to improve genetically are listed below.

Body conformation. From a human perspective, the koi should have a symmetric, tub-like body with dynamic, broad shoulders. The body gives the producer insight into the potential for growth over the adult life of the koi and, therefore, is one of the most important value determinants. Late maturation and lower fecundity ensure a longer ‘show life’. Males with a plumper body form can compete with the females in the show arena for a longerperiod, but reproduce better in an artificial, one-on-one environment without the competition of slimmer suitors.

Swimming style. A quality of ‘graceful’ swimming is sought. For older fish words like ‘dignity’ or ‘character’ may also be added. Swimming style is the aesthetic value of the biokinetic expression of movement, directly related to skeletal and muscular qualities of the fish. ‘Gracefullness’ in the swimming style refers not only to powerful but fluid movement but also to the calming effect it has on the viewer. Feeding behavior is the primary cause of this movement, and possibly tameness brought on through domestication and repeated handling may also help in creating this illusion. To swim ‘lively’ fish must be healthy and in an environment conducive for feeding i.e. low in ammonia concentration and high in dissolved oxygen. Failing these conditions the koi will exhibit a ‘lethargic’ or ‘listless’ swimming style. On the other end of the scale ‘frantic’ swimming is exhibited when the fish are frightened or tries to escape near-toxic, unfavorable water conditions.

Color quality. The brightness is determined by the number of chromatophores in the skin and their propensity for collecting pigments, normally during their development but also later, from the environment. The purity of color to separate into aesthetically pleasing colors and patterns as viewed through different skin layers. Males tend to be brighter at an early age increasing their initial show value.

Color durability. The ability to maintain or increase the pigment ‘loading’ of the chromatophores through synthesis and the ability of pigment cells to migrate through different skin layers to ‘develop’ a pleasing pattern can add to the value of an individual. Intracellular reaction of chromatophores - in particular melanophores and likely cyanophores - to environmental stressors can reduce the value. This could be under both genetic and environmental control and the breeder tries to reduce these sensitivity to the environment.

Color distribution. An aesthetically pleasing pattern to match the particular variety is normally determined by selection. Patterns are not repeatable, but pattern types, pattern edging and shapes do run in families and can be recognized and thus predicted to an extent. Therefore specific bloodlines are more sought-after than others.

These attributes encompass the guidelines set out to nationally accredited judges when judging at koi shows worldwide. As described in Hoshino and Fujita (2006) and De Kock and Watt (2006) judges using a 100-point system award up to 50% to ‘body shape’ evaluation and 20% to colour evaluation. Pattern, ’gracefulness’ and ‘dignity’ carry a 10% contribution each to the overall evaluation. The importance of an aesthetic pleasing body and movement is left in no doubt.

Next part we look at all the factors contributing to the final price.



De Kock, S and Gomelsky, B. (in press) Japanese Ornamental Koi Carp: Origin, Variation and Genetics. In Pietsch, C and Hirsch, P. (Eds.) Carp Biology and Ecology Of Carp. CRC Science Publishers. 400pp.

De Kock, S. and Watt, R. 2007. Koi: A Handbook on Keeping Nishikigoi. Firefly Books Ltd. New York. 159p

Hoshino, Satoru & Fujita, Shuji. 2009. Nishikigoi Mondo. NABA Corporation, Japan. pp392. (English translation)


Servaas de Kock