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Basic Terminology Every Koi Beginner Should Know

Jana worked in animal welfare with abused and unwanted pets. She loves sharing her hands-on experience regarding domestic and wild critters.

Are you new to keeping koi and still learning the lingo? Get help with the words used to describe their bodies, their colouration and more.

Are you new to keeping koi and still learning the lingo? Get help with the words used to describe their bodies, their colouration and more.

A Tale of Two Tongues: English and Japanese

In the graceful world of koi fish, terminology pops up in both English and Japanese. The latter describes aspects of colour, variety and the art of keeping these fish, while English is mostly used to convey anatomy. Here's the question: If you can keep, breed and adore your koi without learning any Japanese, why does anybody even bother? It's true that you don't need to learn a single term to keep koi. However, there are good reasons to know the basics.

  • When keepers discuss a topic, terminology allows instant clarification instead of a lengthy explanation.
  • When terminology is used correctly, you don't look so much like a complete beginner.
  • You can hold your own during sales and shows.

Body Basics

Anyone with fish-keeping experience, no matter the species involved, should be familiar with the basic terminology of fish anatomy. If you are new to fish or never learned about the different parts of your pet, here's a good list to start with.

1. Fins: Pectoral, Pelvis, Caudal, Dorsal and Anal

Koi have two paired fins and three single fins. The paired fins include the pectoral and pelvis fins. The pectoral pair are very recognizable; they are the main pair, located on either side of the fish. In animated cartoons, these are usually the character's hands! The pelvis fins are easy to spot. They are the second pair right behind the pectorals. The single fins are the caudal fin (tail), the dorsal (the back fin) and the anal fin (found near the anal region).

The barbels on this koi are clearly visible on either side of the mouth.

The barbels on this koi are clearly visible on either side of the mouth.

2. Barbels

Look at those whiskers! Called barbels, these mouth protrusions resemble whiskers or fleshy fangs. They allow the koi a certain oriental flavour but, in fact, serve a more practical purpose. Barbels are packed with taste buds, making them some kind of strange tongue. Though technically not tongues at all, these organs help koi find food in muddy waters when visibility is a problem.

3. Vent

The vent is located near the anal area and is as multi-purpose as a Swiss knife. Koi dispose of their waste through the vent. It also plays an important part during mating. Both eggs and sperm are released through this opening.

4. Nostrils

Located on top of the nose, a koi's nostrils are very obvious. This adorable snoot has nothing to do with breathing, however. A koi's nostrils exist for the same reason as barbels—smelling food, but also with the additional survival perk of scenting predators.

5. Operculum

Operculum is a fancy word for the gill cover. Most people are familiar with fish gills, those flaps opening and closing on either side of the creature's face. Much like other fish, koi draw water in through their mouths and use their gills to filter oxygen from the liquid.

Your Colour Guide

Koi colour is always described in Japanese. Don't worry about learning all the words at once. As your interest in the hobby progresses, so will your koi vocabulary. Keep in mind that this remarkable fish is capable of producing new colour varieties, shades and patterns, some barely named yet by the breeder responsible. The following list consists of the most well-known colours. If, for example, your pet is completely white with black and red patches, you have a Sanke.

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  • Sanke: white, with black and red markings
  • Showa: black, with red and white
  • Tancho: white, with a red blotch on the head
  • Utsuri Mono: black, with yellow, white or red patterns
  • Bekko: a solid colour, either yellow, red or white with occasional black markings
  • Asagi: blue back, red belly
  • Kawarimono: includes all-purpose looks, including unusual ones
  • Kohaku: the familiar white with red patches
  • Koromo: white body, with red and any other additional colour.

Terms for Metallic Koi

Metallic koi are very popular in the United States. Their scales are more reflective, and such fish are known as Hikari koi. They're limited to fewer colour varieties than their non-metallic cousins, but they are no less impressive. These shimmery wonders have three categories.

  1. Hikarimuji: Koi with a single colour. Two subcategories are Matsuba (scales have a central marking that give the fish a pine-cone pattern) and Ogon, fish that are either gold or silver or a metallic version of Kohaku
  2. Hikariutsuri: Metallic versions of Utsuri or Showa.
  3. Hikarimoyo: These fish have several metallic colours, usually platinum with red and yellow.

Scales and Skin

Koi terms can also describe the different types of scales and skin.

  • Doitsu: This kind of koi is rarely seen or kept by the casual fancier. They are partially scaled (called mirror-scaled) or have no scales at all (leather-skinned)
  • KinGinRin: This is a type of scale found on koi with normal scales. KinGinRin are normal-sized, come in any colour and have a curious trademark; they line the fish on either side as highly reflective beams. If they are found on red, they are known as KinRin (gold) and when they run over white or black, GinRin (silver).
The long-finned variety is known as butterflies and are particularly graceful swimmers.

The long-finned variety is known as butterflies and are particularly graceful swimmers.

Some More Handy Terms

  • Koi Kichi: People who love koi (as in, somewhat obsessed) are referred to as Koi Kichi.
  • Tategoi: Young fish with show or breeding potential are called Tategoi.
  • Butterfly: The butterfly koi is a long-finned version developed in the nineties. Despite their graceful beauty, butterflies still face heavy snobbery from breeders who prefer the classical koi.
  • Nishikigoi: These are koi from Japan, considered by some to be the best.

© 2018 Jana Louise Smit


Jana Louise Smit (author) from South Africa on June 18, 2020:

Hi Gail. I'm truly happy that you found the information helpful. That's what I aim for. Thank you also for rescuing these fish and caring for them. :)

Gail Marot on June 10, 2020:

I have been looking for information on koi fish for months. This is the most valuable info. yet. I rescued a butterfly koi fish with some other small fish that had been abandoned in an apartment. The author has written such detailed, useful information. I have to re home my friend and I want to do it for the best . Thank you!

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