Koi Fish for Sale

Tips for Selecting the Perfect Japanese Koi Fish for Sale

Koi, an ornamental fish, is part of the Amur carp and is used for decorative purposes in villas, offices, guest houses, mansions in pond-like structures called koi ponds.

Choosing a good koi is a tricky job, given every Koi is unique, and good is a very subjective term. However, here are a few pointers that can be considered while choosing a koi:


A Japanese Koi is expected to live up to 40 years on average. Generally, larger Koi are older (though lengths may vary depending on the breed, diet, health, and genetics). So while buying, one needs to ensure that they have sufficient space to keep the Koi. Determining the age of a Koi is complex and can be determined only by looking at some of the details, like the size of the ear bone or the number of tiny rings on some of the scales.


An average Koi will be between 6 to 8 inches by the end of its first year. Once fully matured, Koi can be between 24 and 36 inches in length. Some ‘jumbo’ varieties of Koi can grow up to 52 inches. Factors that affect the growth of a Koi fish include:

  • Genetics
  • Age
  • Water Quality
  • Pond Temperature and Size
  • Nutritional Blocks

The following size chart shows the length of an average Koi as it matures:

Age Koi Fish Size
1 Month 1.1 inches
6 Months 5.1 inches
12 Months 9.2 inches
2 Years 15.6 inches
3 Years 20.1 inches
5 Years 25.7 inches
7 Years 28.5 inches

Feeding Techniques:

Koi fish can eat anything from tiny bugs and insects to plants and algae to even food such as cereal lettuce. However, a feed should be such that they can eat in about a five-minute period. Koi needs to be served such feeds up to four times a day. A key point to be noted is that it should be avoided to feed Koi before a storm. Rains decrease oxygen levels, and fishes find it difficult to digest food with less oxygen. During the spring and late in the fall, it is preferred to feed Koi with more carbohydrate-rich foods. When mating is in the air, protein-rich food is preferred in early summer. Another fact that may fascinate the readers is that a Koi can go all winter without eating as their metabolism slows down.

Water Types:

Koi need a pond with a capacity of at least 1,000 gallons of water to thrive. A starter bacteria can be put in the pond to convert ammonia into the less toxic nitrate and turn on the filter 1-2 weeks before putting the fish. The water of ponds should neither be distilled nor R/O. A variety

of minerals are required to support Koi. Distilled water added to a bit of seawater is ideal for Koi. Apart from these, the following factors can also be considered while buying a Koi fish:

Body Shape

A good koi should be in the shape of a laser-guided bomb: not too thin, not too thick. It has a rounded nose, and its elliptical body flows from head to thin in a graceful line. It is always uniform in shape, which can be checked by putting the Koi in a bowl. It should be symmetrical and not have any unusual bumps, lumps, scars, or indents. The upper and lower lobes of the fins should be of the same size with no fraying or any other forms of damage.

Skin Quality:

Skin Quality keeps on varying with different breeds and is judged differently. However, all Koi have bright and shiny skin. When viewed in a bowl, it should be bright and lustrous, just like fine porcelain. Edges of scales should be barely discernible if the fish has scales.

Color and Pattern:

Though Koi are of various colors and patterns, they should be strong and even throughout the fish. There should be no faded region with deep, rich, and strong color. These colors and patterns may continue to develop as a Koi grows. They do not have patchiness when they mature.


Before deciding which fish to buy, it is essential to check the health of the Koi. It can be checked by looking carefully at the fish swimming with other Koi. It should be swimming normally with dorsal fins erect, and pectoral fins splayed wide. It should be graceful in its movement with no unusual or exaggerated body movements. When the dealer catches, it should try to evade capture. This signifies that the fish is alert and interested in its surroundings.

While these were some of the features one could consider while buying a Koi, one should note every Koi is unique in nature, and it depends on the buyer’s choice. The term “Good Koi” is very subjective and depends on the buyer’s desires.