About Koi

Koi Terminology and Definitions

For those of you who might not know the difference, I offer the following definitions:

What are Koi?  Koi are ornamental carp, which originated in Japan. More than a century or two ago (at least…no one really knows), the Japanese raised a particular black carp in their rice patties called Magoi. These black/dark brown Magoi were originally raised for food, but somewhere along the line it is speculated that a farmer noticed some off-colored babies and put them aside to raise further. These babies were off-colored genetic mutations of some sort and by continual breeding with each other over time, the beautiful fish of today arose with all the colors of the rainbow.

The common carp (Cyprinus carpio) is the ancestor of all koi

Koi & Their Perceived Value

Here is a video that helps new hobbyists begin to understand Koi and their perceived value. I personally would have titled this piece “Why Koi Fish CAN SOMETIMES be so Expensive”, as most Koi sold are within anyone’s budget that would want them.”Some of the info in this video is a little off, but for the most part it is generally informative if you don’t understand the world of Koi. No matter I can tell you that some people have more money than sense to pay 1.8 million for a fish!


With that said, understand that the world of Koi and their value is very similar to the world of Dogs. Their are mutts, full breeds, and show winners! Yes there are actually Koi shows. Understand now that Koi are not all valuable just because they are Koi! As a matter of fact, most Koi sold in the USA are considered “mutts”. These are low grade flock -spawned fish of poor quality. Here at HKF all of our fish are selectively bred for superior quality.  With that said we still offer various grades of these selectively bred Koi to meet anyone’s budget. Read our website, or better yet come to the farm and we can teach you what makes one Koi better than another, and thus more valuable. This is clearly visible in our grading sytem and pricing.

Understand that the majority of the Koi offspring do not even make the cut here at the farm. Anywhere from 50% to 95% of each spawn is culled and only the smallest percentage make the cut to our retail tanks! So don’t pay too much for “mutt” Koi just because they are Koi. The Koi that do not make it are referred to as “culls” and this is the grade being sold by many places out there! Not here at HKF!  We can show you the difference in person when you come to the farm and you will quickly see the difference in our fish as compared to what you have seen elsewhere.

So Understand the difference in grades of Koi and pick whichever grade suites your taste and budget. You can see out price list and grading system here: https://hanoverkoifarms.com/koi-price-list/

Fin Varieties-

Koi today come in two distinct fin variations. The original Standard fin Koi and, developed more recently, the Butterfly or Longfin Koi.

Standard fin Koi have pectoral fins which are proportional to their bodies and usually short and round to oval in shape. These were the original Koi developed by the Japanese. Within the hobby the Koi purists which have taken the hobby to its highest level usually tend to stay with the original Standard fin Koi. Many of these folks even show their fish just like the dog shows around the world. The All Japan Koi Show in Japan is by far the top show worldwide. This show only allows the original Standard fin variety, and it also limits the show to only fish born and raised in Japan. There are serious standards that each fish must possess to be a contender in this show. We will get into how to judge these standards elsewhere in the HKF website. Some of these top end show fish have sold for hundreds of thousands of dollars!

Butterfly Koi are a cross between a long-finned carp and a standard fin Koi, and are also referred to as “Longfins.”  These fish were developed in Japan originally in an attempt to make Koi have more robust bodies and more total body length. There is one American breeder that contends that he created Butterfly koi, but this is simply not the case. He may have been the first to develop them in the USA however. No matter, as compared to standard fin Koi, the fins of a Butterfly are much longer and can be as long as 3/4 of the fishes body length!  Most Butterfly Koi are domestically raised and bred in the U.S., although there are some imports still available in Japan.  Butterfly Koi are highly sought after by Americans for their beautifully long fins, and today they are available in many of the same varieties as are standard fin Koi. Hanover Koi Farms breeds some of the top Butterfly Koi in the world. Most are even far superior to those produced in Japan and other countries.

Two Soragoi: one with Butterfly fins (left) and one with standard fins (right). The same breed in two different fin varieties.

Scale Patterns- Koi also come in various scale patterns, which also are given particular names and used as adjectives when describing a certain fish or variety/breed of fish.


Wagoi is a term used to describe any fully scaled Koi one with normal scales like any other fish species that most folks are used to. The actual term itself is not used that often when speaking Koi. Probably the only time it is used is when discriminating between a Wagoi and a Doitsu Koi. See Doitsu below for details on that.

Doitsu ( pronounced “Doytz or Doytz-ew” by most) is a scaleless or partially scaled Koi that originated by crossing Japanese Koi to German Mirror Carp.  If you look closely at the photo to the right, you can see that the only scales on the German Mirror Carp run right down the back/dorsal line of the fish. Click on the photo to enlarge it. The rest of the fish is simply skin. The other fish in that photo is simply a common carp relative.

There is also a photo of a Doitsu Hariwake. Click on that photo and you will see the only scales on the Doitsu Hariwake are running down the back but only right under dorsal fin. A classic example of a Doitsu Koi. Hariwake can also come in a Wagoi (fully scaled) version and then are simply called Hariwake. So you can have a Hariwake (fully scaled) or a Doitsu Hariwake variation. See the photo to the right of a Hariwake  (the yellow & white fish) . This fish is fully scaled and it also happens to be Gin Rin. So technically that yellow and white fish is a Gin Rin Hariwake. Gin Rin is explained further below and is the sparkle scale look.

There are many variations of how and where the scales appear on any given Doitsu Koi, but the most common are the scales running down the back. Doitsu scales are much larger and somewhat reflective as compared to the scales of a normally scaled Koi. A fully scaled normal Koi is referred to as Wagoi Koi (fully scaled) as compared to the partially scaled Koi is called a Doitsu Koi as discussed above. Sometimes these Doitsu scales can be difficult to see (as in the photo to the right).  This is also the case depending on the color and pattern of any given Doitsu variety. Many times, however, in Doitsu Koi you can see a very distinct zipper-like pattern going right down the back of the fish. That “zipper” are the actual Doitsu scales all lined up and running down the back. It resembles a zipper. This is especially true when the scales are colored differently than the underlying skin color. So as far as scales types in Koi there are Doitsu (scaleless or partially scaled) and Wagoi (fully scaled), and in each there are varied scale patterns and types. With me so far? I hope so because I am about to make things even more confusing.

Also among these Doitsu scale types are “Dragon scaled” also called “Armor scaled Doitsu” Koi. These are usually the first generation of fish that were bred using one Wagoi parent and one Doitsu parent. In this breeding you will get a mixture of various types of scale patterns. Some may be full Doitsu in appearance, some may be full Wagoi in appearance, and some will be fully scaled but with the larger scales like that of the German Mirror Carp. When they are covered in these large scales it does give the appearance of armor plating. While this scale pattern can be quite striking in certain fish, the armor scaled Koi are considered to be a lower quality Koi.

Gin Rin is used to describe a sparkle-scaled fish. Some or most of the scales actually sparkle like diamonds, which makes these a popular type as well. This sparkle effect is actually due to an excess of a substance called guanine. Guanine is what makes all fish scales sparkle, but in Gin Rin Koi there is an excess of this crystalline nucleic acid which give the Gin Rin Koi this added sparkle as compared to normal fish scales. It is simply another mutation that occurs in Koi. Both Doitsu and Wagoi can come in Gin Rin. In this as well there are a few types of Gin Rin scales that give varied looks to each type, but we won’t go that deep. So basically, Gin Rin is an adjective that is put before the actual variety name of the fish. For example, you can get a Kohaku or a Gin Rin Kohaku. See the photo below for an example of a Gin Rin Kohaku.

A Chagoi (left) and a Gin Rin Chagoi (right)
A German Mirror Carp (bottom) compared with a common carp (top)
A Gin Rin Hariwake (left) and a Doutsu Hariwake (right)

Skin Quality and Luster

Kin is used to describe a metallic Koi. Again it is an adjective used before the breed name. As an example, in the photos to the right there is a Showa and a Kin Showa. The metallic refers to the sheen of the fish, especially in the pectoral fins  and skin luster. Understand that this is not the same as the sparkle scale look of the Gin Rin. Metallic varieties of Koi can be Wagoi or Doitsu versions as well. A non-metallic fish would have clear or flat-colored fins, and a metallic or Kin fish would have a luster or gloss to these fins and body . For example, a Kigoi (yellow Koi) is a non-metallic, non-glossy Koi, with see through fins of sort, and a Yamabuki Ogon (bright, shiny yellow) is the Kin or metallic version of a Kigoi, and is a glossy yellow with lustrous yellow fins and body color. In this variety, however, as in a few others, the metallic or Kin version of a Kigoi is not called a Kin Kigoi. Instead it is called a Yamabuki Ogon. This is just one thing that makes learning all the breed names difficult for some.

I know all of this seems confusing, and it is. I hope I was able to make this clear enough for you to understand. Come to the farm and I can assure you that it can be better explained and shown in person!

A Showa (left) and a Kin Showa (right)


Domestic Koi are simply Koi which were bred here in the U.S. All Koi descended from the Japanese fish, as they were the ones that created them. The primary difference is that the bloodlines in Japan are a little purer still, but that fact is changing very quickly. Many of the original bloodlines in Japan have been lost to disasters like earthquakes, disease, or polluted with crossbreeding. However, a small percentage of the breeders there still create the best Nishikigoi in the world hands down. When speaking of the AVERAGE breeder and AVERAGE fish in Japan, some Domestic fish are just as good in every respect. The primary things that are far better in the Japanese fish are their sizes and the quality of their Gosanke. Gosanke is a term used to classify three separate varieties of Koi combined as a group. They are the Sanke, Showa, and Kohaku. These three varieties are collectively called Gosanke. Some USA breeders have every bit as good a fish in the other Non -Gosanke varieties, and some varieties bred here are even better than most of the same varieties bred in Japan by the average breeders there. Only a few top breeders in Japan produce the largest numbers of the highest quality fish that come form there.

Imported Koi from Japan are Koi that were bred in Japan and shipped to the USA. Many other countries breed Koi as well, but the Japanese by far have some the best available. Some breeders in the USA are catching up quickly especially when you compare the amount of time we have been doing it over here as compared to how long the Japanese have been breeding them.  Most Japanese breeders specialize in three main varieties, the  Gosanke, as stated above. Outside of Gosanke, some American breeders have as good or even better fish in some other varieties for sure though. This is especially true when speaking of Butterfly Koi. This is in comparison with the AVERAGE Japanese breeders. The few top breeders in Japan, however, have Gosanke that are so superior to those bred anywhere else that it will be a long time before we catch up in that area of breeding here in the USA. However, Gosanke are not as popular with the average hobbyist/watergardener in the USA. Gosanke are most popular with folks that are advanced in the hobby and follow the show world of Koi. As breeders, we also appreciate a quality Gosanke, but frankly they do not sell very well here in the USA as compared to the metallic varieties. For this reason, most of our breeding efforts are concentrated accordingly.

You must also be aware of the fact that there are places out there selling Koi at high prices and referring to them as “Japanese Koi.” This is a sales ploy, and it implies that they are imported fish from Japan, but they are not!  Don’t be fooled! Ask the clerk if the fish are imported, and if so, from where. They may just be domestically bred and raised here in the U.S. Other countries that export fish as well would include China, Malaysia, Taiwan, Israel, and some others. However, I personally consider these to be inferior quality and an extreme health risk. Most foreign countries have very poor treatment protocols and no bio-security to speak of.

Koi Standards and Quality: What Makes a Good Koi?

Imported as well as Domestic Koi are usually classified into one of multiple original varieties. There are many newer sub-varieties that are the result of crossbreeding among these original. Each variety has specific colors, patterns, and scale features associated with it. There are many books dedicated to this subject alone, but we won’t get into all that now! Also, there are Koi shows held throughout the world that can be compared to the dog-breeding events held by the American Kennel Club. Koi are judged on skin texture, body shape, color, and pattern, just as specific breeds of dogs are judged for their own characteristics. As an example, you could buy a very pretty dog that is a cross breed between a yellow lab, and Irish setter. This dog could be very pretty, friendly, and a wonderful pet, but it will not be worth as much as a full breed yellow lab or Irish setter. Then, you could buy a full breed yellow lab that is not registered with the AKC, but still be a full breed dog. This would be a little more valuable than the latter. Then you could also get a full breed yellow lab with papers (registered with the AKC), that is even more valuable, and finally you could buy a yellow lab that is not only registered, BUT has all the makings of a show class dog. This would be the most valuable, and the more shows it wins, the more the value rises. All of these dogs are valued accordingly, and all of this is very comparable to the Koi world. Every fish has a value that is based on similar breed and show standards.

Here is a video that helps new hobbyists begin to understand Koi and their perceived value. I personally would have titled this piece “Why Koi Fish CAN SOMETIMES be so Expensive”, as some are within anyone’s budget that would want them.”Some of the info in this video is a little off, but for the most part it is generally informative if you don’t understand the world of Koi. No matter I can tell you that some people have more money than sense to pay 1.8 million for a fish!


Now, with that said, I would suggest that most of you forget it for now! That is, unless you are interested in entering your fish into one of these shows. If and when you advance to that part of the hobby, these facts will become more important. Somewhere along the line, as the Koi industry grew in the U.S. and abroad, something was lost however. In Japan, Koi are primarily judged on skin quality and body shape. Color and pattern are important but secondary. It is my opinion that as the hobby grew here, Americans and others outside of Japan have put way too much emphasis on the Japanese show standards and varieties. This is causing people to turn away from what they truly like. Even though the Japanese created most show standards, and those standards have created gorgeous fish, they will be the first to tell you that you should only purchase a Koi if it appeals to you!

Don’t worry about those standards unless you are into that part of the hobby. I see it all the time here at the farm. Someone will truly love a particular fish, but may not purchase it because they believe it does not meet the show-class standards they are learning, or it may not fall into a particular variety. These same people in most cases do not even show their fish! In short, buy what you like — not what someone else says you should like! We do however carry  Domestic Import Quality fish, which will most definitely qualify for entrance into the best of Koi shows!. Some of our fish that are spawned right here at the farm, are every bit as good as the Japanese imports and I defy you to be able to tell the difference. Anyone that thinks they can tell a Domestic Koi from an Import is dreaming! The main point I am trying to make with all of this, is that advancing thru the hobby takes time. Don’t try and rush through it. Start the hobby buying what you like, and as you learn the differences in quality, then start getting the higher quality and more valuable fish. You must also realize that there is a learning curve of taking care of these fish, and you do nay want to risk fish that are expensive until you have some experience in keeping them.

I hope the above definitions give you a better understanding of the different types of Koi available today.

Identifying Breeds of Koi

This section is to help you begin to understand the different breeds of Koi. I use the word “begin” because you could literally write volumes on this one subject alone. We will give you both photos and written descriptions to help you on your way to be able to identify one breed from another. We will also teach you a fraction of what makes a good fish in each breed.

Understand as well that most of these fish in the photos below are mature, finished fish. As youngsters they look nothing like this in most cases. As a matter of fact that is a whole other volume of information to learn. So don’t expect a fish under 16″ or so to look anywhere near these.  We will have other sections here to help you learn how to identify breeds as young fish, and more importantly what a good one looks like when young.

Let me make it perfectly clear right now that the fish in the photos in this section are extremely good examples of the breed. These fish would cost from thousands to tens of thousands of dollars. So do not use this page and contact me to say “I would like one that looks like this one” and then expect to get it for $20! In most cases I would not have Koi  for sale of this caliber anyway as I keep them as brood stock, and the same holds true for most Koi breeders. I do sell some on occasion when I have excess brood stock however. These fish are very rare to say the least, and that is why they command such prices.

We have only scratched the surface on Koi breeds here. In the future we will be adding more breeds. For now you can learn some of these more common breeds of the Koi world.

Simply click on the photo and it will take you to the details of what makes that breed.

Note: Some of the breed descriptions below are still under construction and might not be available yet







Chagoi Hanover koi farms








Ogon (Varieties)

Kikokuryu (Varieties)

Matsuba (Varieties)

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