HOME > Guidelines for Good Koi

Guidelines for Good Koi and Basic Care

ID Tips for Good Nishikigoi

Form, Color, Pattern are three basic factors for evaluation.

According to the contest screening standard, Koi are evaluated on Form 50%, Color 30%, and Patterns 20%.


Well shaped Nishikigoi with proper height and width that look healthy and powerful are rated high.

Attracted by beautiful color and exquisite patterns, bodily defects are sometimes overlooked.


The vivid red, deep charcoal-black patterns, even colors and beautiful in hue.

Evenly colored, free from shading, such as white snow ones are highly rated.


Well balanced patterns, symmetrical on either sides are highly rated.

Clear patterned-edges (Kiwa) and uniformly colored on top (Sashi) are more highly.


Not cloudy on the head or on the body, and shining wholly are rated well.

Dignity and aroma:

Unbalanced patterns, but bestowed with dignity or aroma of its own are well rated.

Your own taste will anyway play an important role in judging the most appropriate for you.
Try to find out the attractive one of originality, not always finding a fault.

Female and male:

Female: white fair skin, plump belly and larger size.

Male: quick in swimming. Finish is fast and very beautiful, allowing participation in the contest during juvenile.


How to Feed Koi

The water temperature 25℃ is the best condition for feeding.

Nishikigoi goes on fast for about half a year during over-wintering. Do not feed them when water temperature is below 10℃ to prevent from digestion problems.

Need a lot of oxygen for healthy digestion.

To help digestion and absorbing ability, soften by soaking any hard food in water before feeding.

It is recommended to feed in several batches, in such a volume as eaten up within 5 or 10 minutes.

Too much feeding brings about diarrhea state and floating dirt, a sign of digestion problem and ill health. Lessen the food quantity.

Koi Tank Farming

Tank installation site

Select solid and level or flat foundation site.

The site within the reach of water-supply hose is favorable.

The site free from direct sun-shine, rain, snow and etc.

Avoid such places where people come and go very often or may be frightened by door-sounds.

Cover the tank to prevent the carp from jumping out or being attacked by cats or birds.

Filtration device

The higher quality filtration device is recommended for installation, due to limited tank capacity that contains smaller volume of water allowing easy deterioration.

Two units installation is advisable.

Spread clean pebbles (size 0.5 ~ 1.0 cm) to cover the bottom of the tank with thickness of 3 ~ 5cm high.

Pebbles are helpful for filtration, and further serve to firmly fix decoration stones inside.

Coat the outside of glass tanks (rear, right and left sides) with blue or black back-screen for lightproof, thus helping the carps feel easy and look much beautiful.


In case of a water tank, “Shime-gai” is generally prefered.

Too much feeding sometimes causes blockage of the filtration device, resulting in deterioration of water quality in no time.

Periodical cleaning and water-change

When the filtration device becomes dirty, run the water from upside over the device to clean lightly.

Even if raised in a tank, it is recommended to clean the tank keeping carps in the water as they were.

Take bigger stones only out of the container and stir up the pebbles and/or gravels to float dirt or foreign particles in the water.

After a while, filtration device works to suck the dirt or particles. Then, wash out the device to clean up.

Filtration Device for Koi

Generally, it would be ideal if bio-filtration area is 1/3 of water volume of a pond.
For the filtering medium required, secure, at least, the volume nearly equal to 10% ~15% of pond water volume..

In case water volume is only 5-tons, installation of the bigger size of 10-ton use is recommended. That will help reduce the burden of the device.

Koi Ponds

Why don't you send your favorite Koi to a show ?

As for the show, there are so many, ranging from the bigger ones organized on a nationwide basis to the smaller ones for the local customers or traders.

At present, there is All Japan Nishikigoi Promotion Association, a professional group on one side, while many amateur groups or circles are also active nationwide and locally on the other. The latter groups or circles are holding their own shows
(Organized on a prefectural-bases or city-government base).

Why don’t you send your favorites to a contest ?

Koi Contest

Release of Koi :
Procedure after Arrival

Release to a pond

Put the vinyl bag unopened straight to a pond and leave it whole for about 20-minutes.

Then, let the pond water into the vinyl bag about 1/2 filled to mix water.
After that, release Koi into the pond.

After that, release Nishikigoi into the pond.

If you have a “Detached Facilities”, recommend “Salt water bathing”

Let Koi free in the water in which 6kg Salt and 5g “Elvarjyu Ace” are dissolved per 1-ton water. (Adhere to the ratio of Water, Salt and Medicine) for 4 to 7days.
After that, release them.
Do not feed while Salt water bathing.

*Producers or traders usually carry out this salt bathing without fail, even if Koi’s displacement is made in the same facilities.
Advisable to effect salt-bathing whenever changes of circumstances for Koi.

Release into water tank

Replace water and Koi from vinyl-bag into a basin or a tub, then add the tank water in a volume about half of the bag water to mix.

Repeat this procedure several times. Take time till water temperature becomes equal.
Then release Koi only into the mixed water.

KHV Precautions

It has been proved that Koi, subject to the treatment in a raised water temperature for herpes virus will become a virus carrier.

“There is no risk of KHV transmission, if healed naturally on its own, or subjected to the treatment in a raised water temperature.”
Please be aware that it is a big misunderstanding of KHV transmission!

A KHV infected Koi, looks apparently healthy with no symptoms recognizable but may cause widespread infection of KHV during sales, temporary custody or participation in various shows and etc.

The Koi, healed naturally and/or subjected to treatment of the raised water temperature will become the carrier of KHV, source of infection thereof.

Feeding Koi

Copyright © 2018 Matsuda Koi Farm All Rights Reserved.