estanque koi invierno

Koi in winter

Koi in winter behave differently. Here we talk about what is normal and what is not normal. If you have any further doubts after reading this article, please contact us. 

Koi belong to the carp family (cyprinus carpio) and are cold water fish, that means that their body temperature depends on the temperature of their surroundings. They can live in waters with temperatures between 2º to 35º.

If the temperature change is carried out progressively, there is no problem. But a change of temperature of more than 5º in a same day can cause serious problems. In large ponds, especially with sufficient depth, temperature changes are less stressful, while in small, flat ponds, koi are exposed to living the changes more drastically.

Koi can easily survive 2 months to 2º.

Taking into account that the temperature of the body of the koi usually varies half a degree with the temperature of its environment, it is understandable that the metabolism of the fish is very reduced during the winter season.

Generally the koi in winter are usually “parked” at the bottom of the pond.

Koi are hibernating. 

At these water temperatures it is imperative to leave them in peace.


Because they are with a reduced metabolism resting in the pond and if suddenly you approach and make some sudden movement you frighten them and cause them to flee intuitively. Then they have to make a huge effort that causes them a lot of stress.

When the metabolism decreases, the defences also decrease and the koi are more susceptible to diseases such as Saprolegnia (a type of fungus that can live between 3º-33º) and to lie sidewards (usually a problem of the swim bladder).

Attention: Make sure the surface of the pond is not completely frozen. You need at least a good open hole so that toxic gases can escape and oxygen can enter. NEVER – I repeat NEVER – break the ice in case the surface is frozen. The reason is explained above (not to scare). You can get a hole by pouring hot water. To maintain it you can use a heater or special elements of styrofoam.

Do you feed koi in winter?

I just got a call from a client: “Thekla, my koi do not eat. For 2 weeks now they no longer eat. The water temperature is 8º. How long can they be without food?”

koi en invierno

Koi Hacienda: Do you feed koi in winter?

Nature is very wise. Normally, koi stop “asking for food” at around 8º of water temperature. From this temperature on, it is advisable not to feed at all. They can easily survive 2 months without eating (or even more).

Between 8º and 12º we recommend to give them special winter food. This is prepared for easier digestion and thus does not cause too much work for the metabolism.

Can I buy koi in winter?

You can always buy koi 😀

The most accurate question should be: Can I introduce new koi in winter?

When the water temperature of your pond is 12º and less, we will not send the koi. The koi has to withstand the stress of the trip (although we try to put it as comfortable as possible, it will always be stressful) and on top low temperature, would be too much for the organism of the koi. Introducing it when there are high temperatures is easier, but introducing it with cold is very delicate and you have to calculate a long time of adaptation (30-40 minutes).

If a koi is introduced into too cold water, 2 things can happen:

  • the koi lives a heart attack and dies right away
  • the koi lives a “shock” whose consequences may appear days later: behave “weird”, swim “crazy”, float but still breathe and finally die

Good to know

  • Our koi come from the Niigata area of ​​Japan, where year after year there is a hard winter with a lot of cold and lots of snow.
  • A koi kept only in hot water DOES NOT grow more than a koi that lives its rest period in winter.
  • An appropriate rest period is 2 months at 8 degrees.
  • The rest period is absolutely healthy: it reduces the risk of accumulation of eggs, tumors and other metabolic diseases.
  • In areas where the water temperature does not reach 8º, it is advisable to take 2 weeks in the coldest period of the year and put them to fast (for the reason explained above).

And then?

When the temperature rises again, the problems in the pond explode.


Because the metabolism of the koi has to “light up” little by little. While the metabolism of parasites and bacteria reacts much faster. So the “attackers” are ready while our koi begin to “wake up.”

For your koi to survive the winter well and be strong in spring, we recommend the natural product Malamix17  with 17 natural ingredients to increase the immune system of the koi itself.

If you have any questions, please do not hesitate to contact us:  

doitsu Platinum Ogon

The incredible evolution of a doitsu Platinum Ogon into a Ki Kikokuryu

Once upon a time …

During our trip to Japan in February 2016 we discovered with the breeder Chogoro a precious doitsu Platinum Ogon. Chogoro is the breeder “par excellence” of the Platinum Ogon and is sweeping all the prizes in this category.

When Thierry and I “go shopping” in Japan, we feel like two children in a toy store. Or in a candy shop. We are simply captivated and amazed.

For this reason we could not resist buying two precious copies of “normal” Platinum Ogon and a doitsu Platinum Ogon. It looked so elegant.

Koi Hacienda

Koi Hacienda: doitsu Platinum Ogon

We know that Ogon Platinum do not sell so easily. A person has to arrive at our facilities and fall in love with this simple elegance that entails a completely white koi.

Therefore, we do not worry about having it in our pond for more time. A single colored koi will always be a single colored koi. And it is of good quality, it can only improve.

Koi Hacienda

With the time, we realized that the pure white was becoming “dirty“. To such an extent that we have to remove it from the website, because we did not want to offer such a “dirty” koi.

These are the risks that a businessman runs if he is dealing with live animals: they DO NOT evolve as one wants and then we “eat it with potatoes” (like you say in Spanish). Accountably, that is called “depreciating.”

Well … as the body shape was good, we let it swim in our big pond to see where it was going to shoot.

What a great surprise to see this evolution!

Who would have imagined that from this doitsu Platinum Ogon a Ki Kikokuryu would come out?

As some images say more than a thousand words, here a photo:

Koi Hacienda

Koi Hacienda: Ki Kikokuryu

And to make it very evident and not to have to scroll up and down in this article, I’ll make it easy for you:

Koi Hacienda

Koi Hacienda: doitsu Platinum Ogon => Ki Kikokuryu

The photo of the doitsu Platinum Ogon was taken on April 2, 2016. The second photo shows the same koi on October 28, 2017. We are talking about a good year and a half of difference.

And for those who want to have it even more visual, here is the link to the video of the doitsu Platinum Ogon and that of Ki Kikokuryu:

Doitsu Platinum Ogon: 

Ki Kikokuryu:

How can that happen?

Well, I have to admit that we took it completely from unforeseen.

This case shows that no matter how much you pay attention in the selection, they are still living beings and we can not predict the nature.

The only advantage has been that we have purchased a quality koi. And instead of having a quality doitsu Platinum Ogon we now have a quality Ki Kikokuryu 😀

(Or maybe a beni kikokuryu? Who knows … maybe we will live even more surprises with this koi).

For full information of the Ki Kikokuryu, please click HERE

simbología pez koi

Koi fish meaning

Koi are not only coloured fish. Koi have a long tradition based on the “legend of the koi”.

In this article we evaluate the koi fish meaning in 6 different contexts: 

1. Legend of the koi

The basic reading in order to understand koi fish meaning is the “legend of the koi” (soon available to download here). 


simbología koi

Koi Hacienda: The legend of koi – basic reading in order to understand the meaning of the koi

2. Koi in the Japanese language 

The Japanese language is really fussy – or exact, like you wish to call it – compared with our rudimentary European languages. As an example: In Japan you have two words to express love: “koi” and “ai”. 

simbología koi

Koi Hacienda: The koi fish meaning in Japanese languages is “love”

The word koi describes a love for the opposite sex or a feeling of longing for a specific person.

While “ai” has the same meaning as “koi,” it also has a definition of a general feeling of love. “Koi” can be selfish, but “ai” is a real love. Another slight difference is that “koi” is always wanting and “ai” is always giving.

3. Koi in Feng Shui

In Feng Shui (a Chinese philosophical system of harmonizing everyone with the surrounding environment) the koi fish meaning is linked to the ying-yang symbol.

simbología koi

Koi Hacienda: ying-yang symbol in Feng Shui

The white spot in the black part and the black spot in the white part of the symbol are interpreted as the permanent watchful eye of the koi.

The ying-yang symbol represents the perfect harmony between dark and bright / negative and positive as well as the masculine and feminine side.

The circular movement of the koi represents the belief that all things are connected, that all the described opposed and contradictory aspects (black-white, negative-positive, male-female) belong all together and make the circle perfect and complete.

So in Feng Shui koi drawings are used to bring happiness and harmony into the house. 

4. Koi as a tattoo design

A lot of people already know about the koi fish meaning and would not only like to have harmony in the house, but on their own body (others probably just like the drawing of the koi), so they get a koi tattoo

Here it is significant the direction the koi is moving: 

  • upstream: (like the koi in the “legend of the koi”) you are currently in a battle, you encounter difficulties, but you don’t give up
  • downstream: you have reached your goals and do not need anymore to swim against the current. 

The colours used in the koi tattoo are important, too. Here they use the meanings of the koinobori (the flags used for the Japanese Children’s Day the 5th of May)  

  • black: father
  • red: mother
  • blue: first son
  • pink: first daughter 

5. Koi in the spiritual world

Carl Gustav Jung – the Swiss psychiatrist and psychoanalyst – sees the fish as a symbol for the self.

The ancient Egyptians saw in the fish the symbol of the soul. 

In Buddhism the fish is seen as a sign of spiritual power.

Another interpretation is, that the fish are able to take us into the land of our phantasies (remember the mermaids). 

The element water generally represents emotions, indulgence, letting go, cleaning. 

Water is a primordial symbol, which generally embodies one’s own soul life with the conscious and unconscious content.

In every pond there should be a black koi, as it is interpreted to absorb the negative energy. So, if you have a black koi in your pond and it dies, be grateful because it has been taking over the bad energy which would have been going against you or your family. 

6. Special koi patterns and their meanings

Yamabuki Ogon: The yellow koi with the metallic shine is like gold and represents therefor wealth

Kumonryu: Is black, white, grey koi which is changing its colours depending on season, stress, water quality etc. Thus this koi stands for transformation. 

Ochiba Shigure: Is a brown and grey koi. Literally the words mean “fallen leaves in rain”.

Tancho: Are white koi with one red circle on the head, like the Japanese Crane. 

koi tancho signficado

Koi Hacienda: Japanese Crane, koi Tancho, Japanese flag

Doitsu: Doitsu koi are the ones without scales. The translation of doitsu is “Germany” as the breedings without scales was “invented” by the Germans. 

Matsuba: Describes the pine cone pattern of the scales of some koi. 

Kuchibeni: “kuchi” means in Japanese “lips”. Sometimes you can see a koi which has color on the mouth like it would be painted with lipstick.




Koi meaning love:

Koi in Feng Shui:

Definition Feng Shui:

Koi in tattoos:

Koi in the spiritual world:

Koi meanings and patterns:


tategoi tateshita

What is a tategoi ? What is a tateshita ?

What is a tategoi ? What is a tateshita ?

Tategoi and tateshita are koi with great potential. This definition is not a literal translation of Japanese. You also will not find these two words in a Japanese dictionary. They are terms used only among “koi people” to refer to koi “who will improve in the future”.

In order to understand how to define a tategoi, tateshita one has to understand the process of evolution of a koi.

Koi are usually born in May. As soon as they begin to swim, a selection is begun. It is very obvious that you have to have experience and a very good eye to be able to choose the good ones from the bad ones, when the koi measure only a few millimetres.

Why are they chosen when they are still so small?

One female lays up to 300,000 eggs. Many will die, but even suppose only 10% survive, we are talking about 30,000 small koi.

And here we are talking about only ONE female.

And only ONE variety.

With this in mind, it is clear that the breeders must choose as soon as possible as a question of space.

The selection in Japan is so rigorous that only 1-2% of the eggs grow.

tategoi selección

Tategoi, tateshita: The rigorous selection in Japan

This is one of the most distinctive features of Japanese koi (compared to eg those in Israel whose selection is not so strict and therefore the quality is not the same).

I could not stop myself from putting a picture of the net size # 3 (!!!) that I bought in Japan because I was so fascinated:

tategoi tateshita

Net size nº 3 for koi selection

Since they are born in May, the selection starts. En then this selection is selected again. 

And again. 

And again. 

Until January / February of the following year. At this stage they do  the selection of those going for sale and the tategoi. The tategoi are the koi that the breeder considers with great potential. He will set them apart. In most cases the public does not even get to see the tategoi of a breeder as they are in another pond / other greenhouse.

What is a mud pond?

The year advances and the breeder continues to observe his tategoi very carefully. Maybe there are some which doe not meet the requirements of tategoi or just touching them.

At the end of May, early June comes the moment when he decides which of his tategoi will go to “mudpond” (the natural lake) to spend the summer there and develop.

zona Niigata mudponds

Aerial photo of mud ponds in the Niigata area (Japan)

Although these mudponds are very large, the breeder is aware that each koi requires a lot of space in order to develop its growth potential. Therefore how much less koi in the mudpond more possibility of growth for each.

So, the breeder again has to make a selection of the tategoi: Those which have so much potential to enter the mudpond and those who are good, but “not so good”. The latter are called tateshita.

If a breeding is extraordinary with respect to quality and quantity, there may also be tateshita for sale in February / March.

Apart from breeders and some professionals, there are very few people who are able to distinguish a tategoi from a normal koi if they all swim together in the same pond.

It is very difficult and requires a lot of experience and vision.

Who could imagine that this tosai would become such a beauty? It reminds me a little of the story of the “Ugly Duckling”:

evolución koi

You need to have a lot of vision in order to choose the “right”

How to select the tategoi?

Of course the “traditional” criteria count: body shape, intensity of colors, shape of the fins, size of head, quality of skin etc. But after all, the selection is always a PERSONAL decision of the breeder. And a great responsibility, bearing in mind that a tategoi can generate a higher income than a “normal” tosai.

Knowing that it is a personal decision of the breeder, it is understandable and human to err. In both directions: positive and negative. That means: there may be tategoi in the “normal” koi but there may also be a “normal” koi in the tategoi category.

Where can you buy tategoi, tateshita?

The tategoi are not sold.

Well, sorry … most things in the world are for sale.

It depends on the price and how much you are willing to pay. But it is normal that a breeder asks for a much higher price (easily 10x more) if he considers that with that koi could win the title of Grand Champion – which would not only mean a big gain but also an incredible increase of prestige.

I suppose it is obvious that a koi “that will improve in the future” not only depends on the genes, but also that any owner of a jewel like this, must do the maximum possible to give him the best conditions to grow. It is not much use to have a koi with much potential and then give him a poor food. Or leave it in bad water. 

If you allow yourself the “luxury” of a tategoi, takeshita, you should do everything, so that the koi can develop its potential: 

The tateshita are like the second selection of the best and when there is a shortage of place to let them grow, sometimes they get sold. Obviously also at higher prices as they “normal” koi as they are still koi “with great potential”.

And now the good NEWS: 

At Koi Hacienda this year we had the possibility to buy TATESHITA !!!!!

We have:

  • 50 TATESHITA of koi butterfly, different varieties (breeder Suda)
  • 100 TATESHITA of kohaku (breeder Hasegawa)

Soon we will put photos and we will inform you of the date of beginning of the sale by newsletter.

So if you read this article and are not yet signed up for our newsletter, you can do it on our website or send an email to

P.S. celebrate and share it with your friends ?

tratamiento de sal para koi

Salt for koi … the perfect remedy for any koi disease ?

Salt for koi appears to be a “natural” and “universal” remedy to treat any koi disease.

This at least many koi lover told us.

Like any product, salt has its advantages and disadvantages.

And it is not “universal” – it does NOT fit for everything.

Again – and I am aware that I repeat myself – I would like to emphasize an essential and basic issue: Before applying ANY remedy, you must find out the reason for the discomfort of the koi.

Aspirin will serve you when you have a hangover, but not if you have a headache because you banged your head against the door or because you have a tumor.

This article will explain how salt works and what for (and what not) it serves.

Starting from scratch: A koi is NOT a saltwater fish.

Salt is a traditional method used by breeders when there were still not special products for certain diseases. Due to this fact, there are bacteria that are already immune to salt treatment.

From breeders this traditional method has passed to koi dealers and now all koi fans think they have the perfect antidote to any discomfort.


Salt for koi … Why should you put salt in a koi pond ?

We start from the beginning: What causes the salt in the koi pond?

Do you remember the term “osmosis”? Maybe some do not know, others vaguely associate this word with the era of high school during “Physics and Chemistry” classes …

The simplest definition I found is: Osmosis is the spontaneous net movement of solvent molecules through a semi-permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides.


salt for koi treatment in koi pond

Salt for koi: the process of osmosis

A container with a semipermeable membrane in the middle. One side with concentrated sugar solution and the other side with dilute sugar solution. 


The process of osmosis is that the liquid of lower concentration “goes” to the more concentrated liquid. In the case of the drawing, it would be from right to left. As sugar is too large it can not pass the membrane, so that the water particles have to go across to produce an isotonic (balanced) fluid.

The high concentration liquid is called hypertonic.

The low concentration liquid is called hypotonic.

A balanced liquid is called isotonic.

Why do I explain the term of osmosis when we talk about salt in the koi pond?

Because the koi is continuously doing osmosis:

  • Generally tap water has a salinity of 0.05%.
  • The koi usually has a salinity of 0.9% on its body.
  • And its body and gill represent the “semipermeable membrane.”

As the salinity of the koi is higher (0.9%) to the pond water (0.05%) the koi constantly works to reach the isotonic state.

If we add salt for koi to reach a salinity of 0.9% then the koi does not have to strive for osmosis. Less work for the koi – specifically to its kidneys. So it can use this energy in another way such as recovering from an illness.


If your koi are continually stressed, you must find out the cause (not enough oxygen, ammonia and other parameters of water imbalanced, poor filtration, too many koi etc.)

Adding salt to the whole pond should be the last choice you have left, because it is an awfully long process to remove salt.

The salt is not removed – the salt is diluted.

For a better comprehension, I leave you a table which shows this long process:

salt for koi tratamiento de sal para koi

Salt for koi: Dilution of salt after several 10% and 15% water changes

On the left side of the table the amount of salt shown in the water while carrying out constantly a change water of 10%. The last line shows that after 10 water changes of 10% there is still 34.87% of the added salt. The left side of the table shows the same calculations with 15% water change.

For this reason, as I said above, adding salt to the complete pond is something that should be very well thought (a total water change would be a too big contrast for the koi).

Another very important aspect to consider: Adding salt for koi is interpreted as an irritation against which the koi will produce more mucus. This mucus layer contains antibodies and protects them against parasites and therefore is considered positive. But … if the koi continues to consistently produce mucus – in excess – the gills  will be blocked (by the mucus) and less oxygen can enter the koi, which results in weakening the koi and thus salt becomes counter-productive method.

Salt for koi … where it really helps

Immune system

As we have seen, an increase of salinity is considered as an irritation, which the koi “answers” with increased production of mucus, which helps to protect. If it is a sporadic and short-lived remedy it is useful.


As explained above, the increased production of mucus helps to protect. If the parasite can reproduce quickly (because humans do not interfere with proper medication)  the koi can produce too much mucus, which is counter-productive (see above).

ATTENTION: parasites such as Trichodina and Costia reproduce more easily with salt !!! It is efficient against Chilodonella.

So again, if you do not know what parasite is attacking your koi (only the microscope can tell), adding salt presents a great danger.



Bacteria are a very sensitive issue. They are very difficult to see (only with electromicroscope and some only with contrasting liquid), difficult to define and more difficult to combat. If you do not know what you are up against, you should not add salt.

ATTENTION: let’s not forget that we also have bacteria in our filtration system. Therefore, if we kill with salt “bad bacteria” in our pond, also we kill “good bacteria” in our filter (with all the consequences).



Against virus there is not much to do. We can try to help to increase their self-defense, but most of the time we can not do more.



A large wound is a water inlet into the body of the koi. This means even more osmosis effort for the fish. Here salt can help. A quarantine pond with 0.9-1% salinity may be favorable for wound healing.



If you have a peak of ammonia (by too much food, too many koi etc.), salt can help increase the mucus and protect themselves from “burning” of ammonia.

ATTENTION: a CONSTANT increased value ammonia is toxic to koi and should not be remedied with CONSTANT salt.



Nitrites reduce the hemoglobin in the koi’s blood. Hemoglobin transports oxygen in the body. An increase of nitrite is extremely dangerous, because the koi can suffocate. The chlorite anions of the  salt compete with the anions of nitrite and neutralize the toxic effect. Here salt is an appropriate remedy (1 to 3 kg for 1000 liters of pond water).



Salt water damage the pigments and therefore fade the colors of your koi.


Salt and other products

There are very controversial discussions when it comes up to using salt in combination with other products such as permanganate, formalin and anesthetics.

Koi Hacienda always defends the process: First determine the cause of any discomfort and act on time with the right and specific product – not widely. For this reason we think it is better not to mix salt with any other product.


Salt for koi

Salt for koi: any kind of salt is appropriated – but without iodine

If you decide to apply salt for a particular koi with a salt bath, you should use 15 grams of salt per liter of water and bath the koi 10-15 minutes. If the koi begins to lose balance, take it out immediately and re-enter it in the pond. Remember that a salt bath for koi is an irritation – a lot of stress. Stay during this time with koi – do not go away. It may also be advantageous to cover the tank, so that the koi can not jump out.

Summing up: There are only two very specific situation for using salt:

  • when a koi has a large wound => salt bath in a quarantine tank
  • when nitrite values are alarming

In other cases, salt has few or even reverse effects.

Thanks for sharing your experiences with using salt for koi. Simply login to write your comment.




Salt dilution: