Though really only gaining widespread popularity among pond hobbyists over the last few decades, research has found that koi carp have been around for many thousands of years. Cutting-edge mtDNA sequencing supports the commonly held belief that koi are descendants of the common carp (Cyprinus carpio), with most modern koi breeding practices originating in China and Japan around the 4th century. This same sequencing also found that the common carp originated in East Asia, meaning that this is technically the origin of koi, too! Previously, this was a notion that was often disputed.
The aforementioned mtDNA studies additionally found that the large-scale domestication of carp and subsequent selective breeding of them to acquire different colored varieties and unique patterns occurred in China beginning around 6,000 B.C. This has resulted in an incredible boom in the amount and types of patterns, colorations, and varieties of koi now available in the aquaculture industry.
Originally, these brightly colored koi were given to those with political and economic power as symbols of peace, goodwill, and alliances. They were also historically viewed as symbols of wealth, placed in opulent water gardens visible to guests. The former is how koi initially made their way to Europe and, eventually, the Americas, becoming beloved pets rather than representations of power and wealth.
The Shusui koi, specifically, is known as the first Doitsu (scaleless) variety of koi, possessing only two (ideally) to four rows of scales along the center of their back that run symmetrically along either side of the dorsal fin and then join into a single row toward the tail. These scales are most often some hue of blue.
The Shusui was bred in the early 1900s by Yoshigoro Akiyama. He crossed a scaleless German carp (selectively bred to create an easier food source that didn’t need to be descaled before eating, and also known as “mirror carp”) with an Asagi koi. This combination makes Shusui one of the most interesting and unique-looking koi, being one of only two varieties to possess blue coloration (with Asagi being the other).
What Does Shusui Mean?
Shusui, or 秋水 in Japanese, translates approximately to “Autumn water.” This is in reference to the Shusui’s unique coloration and possession of only a couple of rows of scales atop their back, which with some imagination may elicit images of Autumn leaves floating on top of water.
Shusui Varieties & How to Identify Them
Shusui are known for having distinct blue-grey patterning on their backs, usually via the row of scales on either side of the dorsal fin, as well as red (Hi) or yellow (Ki) running along their sides, and white (Shiro) that shows in-between. The blue-tinted scales along their back are typically larger than on fully scaled koi. As the first-ever Doitsu koi bred around 1910, they are often highly coveted and have been bred into several recognized varieties, though they cannot be KinGinRin.
1) Hi Shusui
Hi Shusui possess the typical blueish rows of scales along their dorsal fin, while the rest of their body is highlighted by red or red-orange coloration called Hi, usually most prevalent along their sides and extending up their back. They will also have a decent amount of Shiro. There may or may not be Hi on the head.
2) Ki Shusui
Ki Shusui are much like Hi Shusui, but they possess yellow coloration, known as Ki, rather than Hi.
3) Hana Shusui
Hana Shusui are dominated by Hi coloration, which exists on the sides between the lateral line and back but shouldn’t extend completely to either. These Hi markings will usually be rounded or, ideally, somewhat wavy in appearance. As “Hana” translates to “flower” in Japanese, Hi that is rounded or wavy is more desirable as it more closely resembles flower petals. Hana Shusui can also be Ki, but this is uncommon.
4) Butterfly Shusui
Butterfly Shusui can be any of the other varieties on this list, but they possess the graceful, elongated fins typical of any butterfly koi.
5) Tancho Shusui
As Tancho translates approximately to “red sun,” Tancho Shusui are those that possess a circular Hi marking atop their head. Any Shusui variety on this list can be Tancho. “Tancho” is also the Japanese name for the red-crowned crane, a highly esteemed bird with a vibrant red crown and the namesake of Tancho koi.
How to Appreciate & Judge Shusui Koi
If you’re considering entering your Shusui koi into competitions, there are a number of things that you should familiarize yourself with. First and foremost, know that every competition is different and entirely dependent on the judges themselves – what may be considered appealing to one judge may not be to another. In Japan, judges also value fish based on their monetary value – a fish that costs more may result in an automatic bias in that fish’s favor, while if judged elsewhere patterning and proportions may come more into play. Try to know your audience beforehand, and research judges if you can.
General Guidelines for Judging Koi
Any type of koi should not have any abnormalities, such as missing fins, misshapen mouth, or bruises (unless they were accidentally caused during transportation). They should also not have any parasites, ulcers, or other forms of illness.
Symmetry is also of great importance. The way that the Hi, Ki, and Shiro are arranged from front to back and side to side should be balanced and fairly symmetrical (not strictly symmetrical). If present, patterns that are unique are also favored. The fish should also have a proportional, symmetrical head with proportional, symmetrical fins, and a torpedo-shaped body.
Shusui Specific Judging Guidelines
As Shusui only have a few scales, the proportion and symmetry of the scales that are present are judged quite critically, as is their coloration. The scales should be present along either side of the dorsal fin, ideally one row on either side. More than two rows of scales is judged less favorably. These two rows should join toward the tail to form a single row. Shusui with scales anywhere other than in neat rows along their back will be judged very negatively. The scales should ideally mirror one another on each side and be larger than is average for other koi. Their scales should have at least some blue tint, as this is a trademark of Shusui koi, being one of only two koi varieties with blue coloring. As with Asagi koi, the outer edges of the scales on Shusui should be lighter in coloration so that each individual scale stands out clearly and strikingly.
After checking the general guidelines, like symmetrical fins and a proportional body, and then checking on the symmetry and location of scales, judges will then move on to other criteria. For example, for a Hana Shusui, the judge would then take into account the location and shape of the Hi markings, and for Tancho Shusui they would judge the size, shape, location, and color hue of the Hi marking atop the head. With Hi Shusui and Ki Shusui, the Hi and Ki markings, respectively, should extend past the lateral line onto the back, while those on Hana Shusui should not extend that far. Hana Shusui may have Hi or Ki on the nose and cheeks, so long as it is symmetrical and doesn’t overtake the face or head.
Sometimes, as Shusui age they may develop black (Sumi) markings on the head and face; these are typically not judged favorably, but again will depend somewhat on the location of the competition and the judges themselves.
To learn more about judging criteria for specific koi varieties, check out our other koi guides here!
Keeping Shusui – Health, Growth & Diet
1) Shusui Water Quality
Shusui koi, much like Doitsu, are particularly prone to things like parasites and sunburn as they lack protective scales. Additionally, Shusui that possess a good deal of coloration will likely show some obvious signs if water quality is off. We say “obvious” because you will often be able to visually tell by looking at your Shusui if your dietary or water quality parameters are off. For example, a diet too high in color enhancers, like spirulina, will cause any white portions on the Shusui to take on more of a yellow tint. It can also cause off-color orange spotting, which is not typically desired in Shusui (large, continuous swathes of Hi or Ki are more of a trademark of these koi). Water that has a higher KH, or water hardness, and pH can result in Shusui with random black markings, which is not typically desired.
Like most koi, Shusui needs are best met when water temperature is 50° F to 78° F (10° C-25° C), pH is between 7.5 & 8.5, dissolved oxygen is above 7 parts per million (ppm), salinity is kept very low between .05 & .15 parts per trillion (ppt), and there are only 75 to 100 ppm of total dissolved solids (TTDS), such as metals, minerals, salts, and sulfates.
2) Price of Shusui
Shusui koi tend to be more on the expensive side due to their unique breeding and appearance, being that they have only a select few scales and are one of just two koi varieties to possess blue coloration. You can sometimes find young, smaller (under 8 inches long) Shusui for around 100 pounds or dollars, though you may get lucky and win a lower bid (if bidding is allowed). Adults can easily be well over 1,000 dollars or pounds, depending on the exact variety. Of the Shusui varieties, Ki Shusui are usually the most expensive as it can be difficult to obtain their striking yellow coloration. Hi Shusui are most common and therefore less expensive, while Hana float somewhere in the middle. If any of these varieties are butterfly or Tancho, it can add to the cost. If you find a particularly cheap Shusui, you may want to question this as cheaper fish may have come from poorly operated fish farms.
When purchasing, you should also factor in their water quality needs and the fact that proper aeration and filtration will be needed if these are not things already in place in your pond.
3) Shusui Temperature
Though not incredibly well-studied, it seems that water temperature can play a hand in how koi look. Apparently, colder water lends to darker red or yellow coloration, while warmer waters can result in less vibrant hues over time. This could be related to changes in fish metabolism as temperatures shift, and resultantly how they absorb nutrients that impact coloration. One theory posed by the study linked above is that colder water slows the metabolism, so those nutrients stay in the fish’s system longer even though feeding occurs less frequently.
As mentioned previously, Shusui (and all koi) prefer water temperatures between 50° F to 78° F, or 10° C to 25° C. Additionally, make sure that your pond has varying depths to allow for your koi to swim to different depths to help naturally regulate their body temperature as needed.
4) Shusui Diet
As Shusui koi were bred directly from hardy German mirror carps (scaleless carps), Shusui, like other types of Doitsu koi, tend to have stronger immune systems as they weren’t bred solely from other koi or inbred. Nonetheless, a balanced diet is still essential to their health! To help develop and maintain healthy coloration, colorful Doitsu koi are often fed diets with color enhancers, such as those containing spirulina or krill, as well as those with ample (>30%) protein to aid in proper growth.
In particular, studies have found that feeds with high carotenoids result in a greater concentration of carotenoids in the skin, therefore leading to more vibrant coloring in yellow and red koi, such as Hi and Ki Shusui. If you have a Shusui, you may wish to amplify the blue coloration so it appears less grey or black – in this case, you’d utilize a food with supplemented astaxanthin, spirulina, and/or guanine, as these have been found to particularly amplify blue and purple coloration.
These color enhancers are of lesser importance if you don’t wish to show your fish at shows. Otherwise, though, the dietary needs of Shusui are much the same as most other koi.
How to Breed Shusui Koi
Breeding any koi can be tricky, but is especially so with Shusui. Simply due to the nature of genetics, and the incredible amount of chance and nuance involved in coloration alone, it is very difficult to obtain exactly what you’re looking for with any koi breed, unless you’re a professional with an established line of Shusui. If you try to breed using a mirror carp and an Asagi as was traditionally done, there is a high likelihood of obtaining koi with patchy scaling on their sides and elsewhere instead of just on their backs, as well as coloring that is not consistent with Shusui. If you have two Shusui parents, breeding is certainly easier but it will still be difficult to obtain exact traits (such as the color and patterning specific to Hana Shusui) unless you are very experienced and know the history of both bloodlines.
What is the Cost of Shusui & Where to Buy Them?
As mentioned previously, Shusui are typically on the higher end of expense when it comes to koi varieties, though this does depend on the particular type of Shusui and whether or not you can get lucky with bidding. Juvenile Shusui, as with any koi variety, are generally more affordable, usually closer to 100 pounds or dollars, while adult Shusui, just as with any adult koi, will always be pricier and can range from several hundred to several thousand dollars. More common Shusui such as Hi Shusui will tend to be on the lower end of the price range, while highly sought-after and more difficult to breed types like Ki Shusui can easily be several thousand dollars or pounds for an adult, and a few hundred to over 1,000 for a juvenile.
As with any koi, these prices are quite variable and depend on the seller and location. We encourage you to check with your local breeder or a reputable online breeder for more exact information. Be sure to purchase Shusui, or koi of any type for that matter, only from reputable breeders. A reputable breeder should display their credentials on their site and/or in their shop. You can also determine whether or not a breeder is ethical and trustworthy by checking out koi forums – word of mouth travels fast, and koi owners are happy to provide info on both good and bad breeders.
Oftentimes, cheaper koi come from large fish farms or shady operations that don’t prioritize the health and wellbeing of the fish. Koi from non-reputable sources could be mistreated or have illnesses or parasites from being stocked with too many other fish or not being care for properly.
