The Ideal Koi Body

Novice koi hobbyists usually buy their first few koi based solely on color and pattern that they like. These are important factors in choosing a koi, but veteran koi judges will tell you that body conformation should be a koi hobbyist's first consideration in choosing a koi. In fact, the scoring sheet of most koi judging events gives 50% weight to koi body conformation. Body conformation is therefore much more important than what most people think.

First and foremost, a koi must not have any deformities, i.e., missing fins, crooked body, etc. It must be healthy, with no signs of ulcers, open skin, smashed mouths, disease, or infections anywhere in the body.

Figure 1. This koi was released in the river by

its Japanese breeder for something that most

of us will not notice: a mild spine deformity

The head of the koi must be symmetrical and of correct size in relation to its body - not too big, nor too small. If the transition from the gill plate of the head to the body is not smooth, then the head is probably incorrectly proportioned. The snout must also be of the correct shape and size - not too short or flat that the koi looks like a parrot, nor too protruding. Watch out for excessively large or small fins - traits easily overlooked by a novice.

Novice hobbyists tend to look at color and pattern first before body conformation probably because they are more familiar with these criteria, since most literature describe pattern and color criteria more comprehensively than body conformation. Then again, finding the right words to describe a 'correct' body can indeed be difficult. Thus, hobbyists become familiar with it only after looking at many, many photos of what a 'good' body is.

The body of a koi must conform as closely as possible to the industry-accepted standard, i.e., it must be thick and torpedo-shaped (large at the middle and tapering gradually towards both ends). It must be massive at the tail stout and shoulders. Excessively fat or thin koi must naturally be avoided.

No koi is perfect, so a koi must not be judged by its imperfections. In fact, some textbook imperfections actually enhance how a koi looks - this is the reason why judging a koi does not consist of totaling up its individual pluses and minuses. Instead, a koi is judged as one total package in terms of how pleasant it looks and how it carries itself.

Figure 2. Example of a koi that still lacks body mass;

this is a good-looking koi nonetheless

Figure 3. Examples of koi that have good body

volume without being too fat; compare these koi

with the ones in Figures 1 and 2