We have created this article and checklist guide to help you diagnose if your koi is sick by its symptoms.

It is devastating to see your koi friends sick, and when our customers try to find quick answers or pictures of sick koi, they find it can be overwhelming and can make it even worse.

Use the quick reference koi health checklist, the table of symptoms, and table of diseases to diagnose your koi better.


Read on for help diagnosing koi health issues…

When a koi dies, it is very sad, but when your whole pond dies, it is an absolute tragedy. This type of loss can sometimes even drive people out of the koi hobby forever.

While it is an unfortunate topic, it is incredibly important that koi fish owners learn to quickly diagnose the symptoms of a koi health issue to be able to provide support and save other koi from dying.

In this article, we have compiled our research from the farm into an extensive, yet simple guide to catch koi sickness as soon as possible and diagnose correctly. Not only will your koi be happy and healthy, you will save precious time and money by ascertaining which treatments will most likely be effective.

Keep this guide and refer back often, so when illness does happen, you can act swiftly and confidently!

By becoming familiar with koi behaviors and a little careful observation, you will be able to catch illnesses early as well as provide excellent preventative care. We hope this guide provides comfort and guidance on how to treat koi that are sick to keep them alive in your family as long as possible!


How to Diagnose Sick Koi – Table of Contents

Below this checklist download, you will find more information on how to manage sick koi fish in your pond as well as a table of diseases and symptoms you can search to learn more. Start by downloading our FREE Koi Health Checklist. 


We’ll Email You Our Farm’s Koi Health Checklist


NEW one page document to easily reference for a quick diagnosis!

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How to Physically Observe Koi for Health Diagnosis

Observe behavior both when they are alone and when you feed them.

The simplest way you can catch signs of disease or stress early is to become familiar with your koi’s behaviors. Sick koi will exhibit common patterns and are easy to spot.

You will want to first observe their behavior without them noticing you. Koi will get to know you by sight. They may make movements towards you or for your attention if they see you. Also, they’ll become used to you approaching to feed them, and even a sluggish koi will move quickly if it is anticipating food!


How do I Know if Koi are Healthy?

Look for any koi fish floating on their side, but are alive and have separated from the group. Self isolation points to a possible bacterial infection as does a fish that is sluggishly floating by the waterfall/return pipe or drain.

If you see several koi swimming erratically, rubbing itself along bottom or wall, or jumping out of the water (flashing) this is often caused by parasites.

Next, pay attention when it’s feeding time. Pay careful attention to new koi and any that are not eating, or seem disinterested in feeding. Loss of appetite or erratic feeding is present in almost all cases of stress and illness, and is a sure sign that you should investigate further.

Use our checklist to diagnose their patterns and see if they are acting normal. We have a list of symptoms, diseases, and treatments at the end of this article.


5 Areas to Analyze for Koi Diseases

Check their feces, water quality, physical body, changes in koi appearance and even past death patterns to help figure out the cause of the koi illness or loss. Act quick, but do not jump to conclusions in your koi health diagnosis.

Use the koi health checklist alongside the information in this article.


1. Feces/Waste

If you see floating or gelatinous feces, this means the koi has indigestion from a scrape in the intestinal lining. Normal koi feces should sink and dissolve in the water right away.

Consider what your koi might be eating for food or found in the pond.


2. Water Quality

Water quality is the single most important factor in you koi health.

If you are unsure or need a refresher, here are some tips for improving the nitrogen cycle in your pond. If you are wondering how to tell if your koi fish are stressed, testing the water is the first place to start. Brown or cloudy water of high turbidity is always unhealthy. Water should be fairly clear, but even water that appears clear to the naked eye may not be in the healthy range. Always test koi pond water often or anytime you observe sick or stressed koi. There should be very low or zero ammonia/nitrites, as higher levels can have quick devastating effects.


3. Physical Body Examination

If you have observed any unusual behavior patterns, you will need to physically examine the suspected koi.

You can diagnose a lot with the naked eye but if you have access to or invest in a small microscope, you will be able to look at the scales and get a much clearer picture. Don’t feel daunted by the idea of a microscope, a simple inexpensive one will work great, and it makes it much easier to diagnose.

At the end of this article is an in-depth table that will help you decide on if koi has a symptom of diseases. Refer to this symptoms and diseases table once you have observed any sick koi.

Externally, check if there is any opaque mucus on the body, or worm-hole like appearance on scales. You may visibly see small parasites which may be rod shaped (anchor worm) or disk shaped (argulosis, argulus infestation or fish louse).

Run your hands along the body, if it has lost its natural slipperiness and become dry or sandpapery this could indicate chilodonella, gyrodactylus or dactylogyrus.

Unhealthy koi may have scales that have risen up from the body, like a pinecone that has released its seeds. Red congestion of skin or mouth and any bleeding are also common symptoms.


4. Changes in Koi Appearance

Eyes – Koi eyes can give you many clues about their illness. Are they popping out, or sunken in? Are they infected or even beginning to rot? If you see any koi with abnormalities in their eyes, refer to the above table for specific diseases.

Abdomen – The abdomen may become swollen due to bloating. Also look for damage or redness around the gills or mouth. A koi who cannot breathe properly will deteriorate fast, so catching this early is  a good method of how to save koi fish from dying.

Gills – Infected gills will often have white secretion or abnormal mucus, it may also be grey or yellowish in color. You may notice the base of the gills are white, or see white when they are open for respiration. If the gill covers remain open, instead of opening and closing during respiration, this is a sign of parasites.


5. Death Patterns

In the heartbreaking event of koi death, noting the patterns can help identify the cause to save the others in your pond or prevent more tragedies in the future.

If you have a mass die-off, you might have a hypoxic (oxygen deficient) pond.

We cannot stress enough how important healthy water is for koi. If your water is oxygenated, than you may also have a high density bacterial or parasitic infection. Did you recently introduce new koi without doing a proper quarantine? This is a very likely cause, as sick koi can spread its illness to the others very swiftly due to the fluid shared environment.

There is also the possibility that a poisonous substance got into the water, quickly killing all koi. Any construction happening nearby or heavy rains that may have caused chemicals to be introduced are probable culprits? Your koi pond is a delicate ecosystem, that needs protection from unwanted elements.

A very common mistake is that pond owners add fresh water in water change and forget that the Chlorine in fresh water kills Koi overnight. It happens more than you might think.


Oxygen deficiency may be the cause if you see the larger, fatter koi die first.

If a few koi are dying everyday, even if no abnormalities were observed the day before, this may be caused by koi herpes virus or columnaris, another bacterial infection.

If you see koi swimming lethargically or erratically around drain pipes or waterfalls and then dying, suspect that it was a parasite such as dactylogyrus or gyrodactylus.

How to Save your Koi Fish from Dying

Once you have detected an illness, act quickly to restore health and stop the spread to other koi.

Parasites can be physically removed. Along with parasite medication, you can help your koi regain wellness by removing any visible parasites gently with tweezers.

Both bacterial infections and parasites can be treated medically:

  • Bath Treatment Types: If you are sure your pond water is healthy and only see a single or several koi exhibiting signs of sickness, you can quarantine these fish for treatment. This bath type treatment is both effective and cost efficient, as the volume of water that needs to be treated will be greatly reduced.
  • If it is Pinecone Disease: You can alleviate pressure by gently draining abscess before bath treatments. Please be extremely careful and don’t work outside of your expertise and comfort with you koi.


Preventative Measures for Better Koi Health

Koi have long lifespans, using preventative care will be the best way to keep your friends healthy for a long time.

Feed Options – Do not discount the importance of the best quality koi food. As with anything, you get what you pay for. In the short term, you may not notice a difference, but the long term health of your koi will be greatly enhanced by always feeding them quality food.

Water – This is the single most important factor in keeping koi safe from illness and stress-free! They live in and breathe the pond water; unbalanced water will have swift devastating effects for you koi. Understanding and following these tips for improving nitrogen cycle and using a biological koi pond filter will give you the know-how needed to maintain a beneficial environment. Always check water quality by eye and with test kits.

On top of keeping ammonia and nitrites as close to zero as possible, healthy water is oxygenated water. Running water/waterfalls can help a large pond stay aerated, but may not be enough. It is best to prepare an extra air pump to make certain there is enough aeration. Your koi need plenty of fresh oxygen to breathe!

Plants will filter and oxygenate your pond, and they add beauty to your environment and experience, but require careful strategizing on your placement! Hungry koi will most likely nibble on plant roots. The plants will die and the debris will then dirty the pond. Proper plant selection and set up will give best results. If you decide to utilize plants, they should be placed where koi cannot eat them.

Always check after feeding to see if there is leftover food falling to the bottom. Overfeeding can lead to high ammonia in the water as the excess begins to rot. A good rule of thumb is only feed them as much as they vigorously eat in a minute’s time. Feed them like this twice a day. READ MORE ABOUT KOI FEEDING

Quarantine any new or suspected sick koi – All of your care can be thrown off balance if a sick koi is introduced into the pond. Follow this koi quarantining tank process when introducing new koi into your pond. We recommend quarantining even if you highly trust your koi source. A little extra precaution can prevent a tragedy.

Learn more about using medicated koi food on our blog!



Koi Diseases by Symptoms Table


Sort through all 54 diseases that could be harming your koi. Use the search feature to look for keywords, change the amount of results that are being shown, and use pagination to select a different page.

Original Source: ZNA (Zen Nippon Airinkai) Magazine. Translated with permission by Kodama Koi Farm

White cloud like opaque mucus on the body surface.White Could disease, Chilodonella, Ichthyobodo, White Spot disease, Trichodina, Gyrodactylus, Dactylogyrus.Body/External
The body surface is opaque and cloudy.Chilodonella, White Spot disease, Cold.Body/External
Abnormal secretion of mucus.Gyrodactylus, Dactylogyrus, Columnaris disease, Bacterial White Cloud disease.Body/External
Loss of mucus/slime coat (on skin), skin feels like “sandpaper”.Chilodonella, Gyrodactylus, DactylogyrusBody/External
Numerous white spots.White Spot diseaseBody/External
Red congestion or bleeding.Chilodonella, Ichthyobodo, Trichodina, Gyrodactylus, Dactylogyrus, Argulosis, Epistyliasis, Dropsy (Pinecone disease), White Spot disease, White Cloud disease, Edema disease.Body/External
“Worm-hole” like appearance of scales with white spots on the skin.EpistyliasisBody/External
Red congestion on the fins. Fins become split, like a broom.Columnaris diseaseBody/External
The scales are coming off. Skin loses slime coat/mucus, may become/appear white.Columnaris diseaseBody/External
Mold or fungus stuck to the body.Fungal infection, Hole disease.Body/External
Scales rise up/protruding in a particular area or entire body, like a pine cone.Pinecone disease, Hole disease, Epistyliasis, White Cloud disease.Body/External
Holes on the scales/skin.Hole diseaseBody/External
Holes on the scales/skin as well as other parts of the body.New hole diseaseBody/External
Red congestion, red spots, and/or ulcers on the body.Red disease or Motile Aeromonas, New hole disease, Hole disease.Body/External
Swollen abdomen.Pinecone disease, Intestinal Thelohanellosis, Cold.Body/External
White or pale pink tumors.PapillomaBody/External
Protuberant tumors only in the red/scarlet parts of skin.Hikui disease (red color/pattern rot disease) Body/External
Translucent, rod-like parasite that is approx. 0.2 inches (5mm) to 0.4 inches (10mm) in size. Anchor Worm (parasite).Body/External
Translucent, disc-shaped parasite that is approx. 0.2 inches (5mm) in diameter.Argulosis, Argulus Infestation, or Fish LouseBody/External
Anus becomes red or bleeding.Overfeeding, bloating of the abdominal region, poor digestion.Body/External
Body of juvenile Koi becomes swollen and transparent.Edema disease.Body/External
Gathering around the water return/waterfall.Hole disease, White Spot disease, Gyrodactylus, Dactylogyrus, Chilodonella, Ichthyobodo, Columnaris Disease, Apiosoma, Myxobolus Koi infection,, Dropsy (Pinecone disease), Edema disease.Swimming & Grouping
Gathering around the water outlet; bottom drain/skimmer.Chilodonella, Gyrodactylus, Dactylogyrus, White Spot disease, Edema disease.Swimming & Grouping
Will not come up to be fed.White Spot disease, White Cloud disease, Argulosis, Hole disease, Pinecone disease, Ichthyobodo, Chilodonella, Dactylogyrus, Gyrodactylus, Columnaris, Myxobolus Koi infection, Intestinal Thelohanellosis, Apiosoma.Swimming & Grouping
One or several Koi swim separately from the rest of the group. Stays away from other Koi in the corners/bottom of pond.Gill disease, Argulosis, White Spot disease, Columnaris.Swimming & Grouping
Koi stays still on the bottom of the pond.White Spot disease, Trichodina, Chilodonella, Ichthyobodo, Argulosis, Myxobolus Koi infection, Gyrodactylus, Dactylogyrus.Swimming & Grouping
Koi is laying down at bottom of pond.Sleeping Disease, Cold.Swimming & Grouping
Swimming slowly and lethargically.Chilodonella, Columnaris, Dactylogyrus, Gyrodactylus, Argulosis, Myxobolus Koi Infection, Apiosoma, Edema disease, Dropsy, White Cloud Disease, Cold, Bloating of the abdominal region.Swimming & Grouping
Floating at or near surface of water.Argulosis, White Spot disease, Myxobolus Koi infection, Gyrodactylus, Dactylogyrus, Trichodina, Chilodonella, Columnaris, Ichthyobodo, Edema disease, Apiosoma, KHV (Koi Herpes Virus).Swimming & Grouping
Rubbing against the walls or bottom of pond.White Spot disease, Argulosis, Anchor Worm, Epistyliasis, Chilodonella, Myxobolus, Gyrodactylus, Ichthyobodo, Columnaris.Swimming & Grouping
Shaking the dorsal or pelvic fins.Anchor Worm.Swimming & Grouping
Swimming/reacting hyper sensitively.Anchor Worm, Argulosis, White Spot disease, pH shock.Swimming & Grouping
Jumping out of the water often/repeatedly.Anchor Worm (parasite).Swimming & Grouping
Swelling in the pectoral region with sagging abdomen which is partly constricted.Pectoral swelling, sagging abdomen.Body/Appearance
Swollen and curved abdomen.Bloating of the abdominal region.Body/Appearance
Becoming skinny due to loss of flesh on the dorsal region.Chilodonella, Bloating of the abdominal region.Body/Appearance
Bulging eyes or eyes popping out.Pinecone disease, Bloating of abdominal region. Body/Appearance
Sunken eyes.Chilodonella, Bloating of the abdominal region.Body/Appearance
Rotten and infected eyes.Hole disease, Columnaris.Body/Appearance
Deformed or damaged mouth, fins, or gills.ColumnarisBody/Appearance
Convulsions, or windy/erratic swimming.Atrophic LoinBody/Appearance
Becoming white around the gills.Chilodonella, Gyrodactylus, DactylogyrusGills
The gills become white due to abnormal secretion of mucus.Gyrodactylus, Dactylogyrus, Ichthyobodo, Chilodonella, Trichodina, MyxobolusGills
The base of the gill covers become white.ColumnarisGills
The white gills are observed when the gill covers are opened.Columnaris, ApiosomaGills
The center of the gills become gray or yellow and is damaged.ColumnarisGills
The white granular spots are observed on the gill tissues.MyxobolusGills
The gill covers remain open.Myxobolus, GyrodactylusGills
The gills become reddish black.MyxobolusGills
Drastic mass mortality.Oxygen Deficiency, Columnaris, Red Disease or Molile Aeromonas Disease, KHV, Poisonous SubstancesHow Koi Died
Several Koi die every day.Columnaris, White Cloud Disease, Fungus Disease or Saprolegniasis, Parasitic or Bacterial DiseaseHow Koi Died
No abnormalities were observed until previous day. However, a few Koi suddenly start dying every day.Columnaris, Gill Rot DiseaseHow Koi Died
Koi dies after making frantic efforts.ColumnarisHow Koi Died
Koi swims inactively around the pouring water pipe and dies.Columnaris, MyxobolusHow Koi Died
Koi whose body surface solely and slightly becomes red dies.ColumnarisHow Koi Died
The bigger or fatter Koi starts to die first.Oxygen DeficiencyHow Koi Died

The Symptoms, Treatment & Control of Fish Disease Table


We’ve outlined 12 common diseases and included their symptoms, season, and tips for treatment. Use this table with the koi health checklist and the Koi Diseases by Symptoms Table to identify the source of the health problem of your koi.

On mobile, scroll to the right to see koi treatment and control options.

Original Source: ZNA (Zen Nippon Airinkai) Magazine. Translated with permission by Kodama Koi Farm

DiseaseSymptomsSeasonTreatment & Control
Anchor WormThe infected sites become colored, congested, and rigid because of abnormal secretion of mucus and proliferation of epidermal cells. The size of rod-shape parasite is 3mm to 12mm, so it is easy to find the parasite sticking to the fish.Spring to Autumn.
59°F (15°C) or higher water temp.
Removal with tweezers or medications.

Trichlorfon 0.2 - 0.5 ppm to kill Anchor worm’s larvae. Use it 2 - 3 times every 2 - 3 weeks

Demilin 2g/t (53.6°F (12°C)) or higher water temp.
Argulosis (Fish Lice) Infected Koi wiggles their pectoral fins and shakes their dorsal fins. Also, Koi displays violent erratic swimming and scrapes itself on the bottom or on the wall of the pond.Spring to Autumn.
59°F (15°C) or higher water temp.
Removal with tweezers or medications.

Trichlorfon 0.2 - 0.5 ppm to kill Anchor worm’s larvae. Use it 2 - 3 times every 2 - 3 weeks
White Spot DiseaseTiny white spots are observed first on the head or pectoral fins, and the infected sites are extended to whole body. The infected Koi often scrapes the body sides to the bottom of the pond, loses appetite, gathers near the water inlet, hangs beneath the water surface, or moves less and less on the bottom of the pond.6°C (43°F) to 25°C (77°F) of the water temp.Bath treatment with:
1) 5kg (11lb) of salt / t (264 gallons) for five to seven days
2) 10kg(22lb) of salt / t (264 gallons) for one hour in a day for three days.
3) 2 g of Methylene blue / t (264 gallons) for three days
4) 0.1 to 0.2 g of Malachite green for three days.
5) 20 to 25 cc of Formalin / t (264 gallons)
6) Warm the water temp. up more than 28°C (82°F) so that the life cycle of the parasites stops naturally.
Ichthyobodosis (Costiosis) The infection causes the white cloud like opaque mucus and erosion on the body surface. The infected Koi loses the appetite, gathers near the water inlet, hangs beneath the water surface, moves less and less on the bottom of the pond. Once gills get infected, Koi can not breath and die.November to April1- 20 to 25cc of formalin / t (264 gallons) for two to three days.
2 - 2 to 3g of potassium permanganate / t (264 gallons).
3- 5g of potassium permanganate / t (264 gallons) for one hour in a day at
every two days for three times.
4 - 200g (7oz)of potassium permanganate/ t (264 gallons) for five minutes.

※ 3 and 4 are only performed to Koi of three years or older. Do not exceed the time of bath treatment. Stop the bath treatment if any abnormalities are observed such as swimming with their nose up on the water surface.

5 - 6 to 7kg (13 to 15.5LB) of salt / t (264 gallons ) for five to seven days.

6 - 10 ml of Pro Form-C / 100 gal. three times daily with 25% water change.
Chilodonellosis The infection can be observed on gills and the body surface as well as fins. The infection causes the white cloud like opaque mucus on the body surface. The infected Koi loses appetite and weight, hangs beneath the water surface, and moves less. When gills are infected, the Koi gathers around the water inlet due to breathing difficulty. In severe case, the skin becomes like a sandpaper. Also, the congestion is observed on the skin.Under 20°C (68°F) of the water temp. Especially between 10°C (50°F) and 15°C (59°F) of the water temp.Be alert not to get the infection after Koi Show or Koi Hunt.

Pay attention when the water temperature is low.

The treatment and control for Chilodonellosis are same as Ichthyobososis. See the section of treatment and control for Ichthyobososis.
Trichodinosis (Cyclochita)The infected surface body becomes thicker due to the excessive mucus secretion. The infected Koi becomes anorexic and floats close to the water surface. Koi gathers around the pouring pipe because of breathing problem when gills are infected. Be extra care not to get infected on the fry because the infection leads to death easily.All seasons, especially from autumn to winter.Treatment and control for Chilodonellosis are same as Ichthyobososis. See the section of treatment and control for Ichthyobososis.
Gyrodactylosis (Fluke)
The gills are mainly parasitized and become white due to the excessive mucus secretion. The infected Koi becomes anorexic, floats close to the water surface, and moves less and less. When the fins and the body surface get parasitized, the skin becomes bloodshot as well as white cloud due to excessive mucus secretion.All seasons.1 - 20 to 25cc of formalin / t (264 gal.) for three to five days.
2 - 3g of potassium permanganate / t (264 gal.) for two hours.
3 - 5g of potassium permanganate/ t (264 gal.) for one hour.
4 - 200g (7oz) of potassium permanganate / t (264 gal.)for five minutes.

※ 2, 3, and 4 are only performed to Koi of three years or older. Do not exceed the time of the bath treatment. Stop the bath treatment if any abnormalities are observed such as swimming with their nose-up on the water surface.
Columnaris (gill rot, mouth rot, fin rot, and dermal rot disease)The infected Koi loses appetite, gathers near the water inlet, hangs beneath the water surface or moves less and less. The disease causes the mortality of the Koi due to the emaciation. White and yellow substances are observed on the whole body. The body covers with cloudy mucus gradually. Scales and mucus come off consequently, and it makes the fish appear as if covered in white rags.20°C (68°F) of the water temp. or higher.The disease must be found at early stage like when only one of the gill is closed.

1 - 6 to 7kg (13 to 15.5LB) of the salt /t (264 gal. ) for five to seven days.

2 - Oxytetracycline with salt5 -6 kg /t (264 gal.) for 10 days

3 - Oxolinic Acid with salt 5 -6 kg /t (264 gal.) for 10 days
Pine cone diseaseScales of infected Koi raise up, and heavily infected Koi resembles a "pine cone". In most case, the skin is bleeding. Swollen abdomen and pop-out eyes are also observed. Infectivity is weak when scales raise up on the whole body. However, when scales raise up partly and spread on the whole body gradually, the infectivity tends to be strong. Aeromonas hydrophila causes this disease. Overeating starch and fat could cause the disease, too.Early spring.Aeromonas is not very infective. Pay attention to water quality and keep COD under 5ppm

1 - Oxytetracycline with salt 5 kg /t (264 gal.) for 5 to 7 days

2 - Oxolinic Acid with salt 5 -6 kg /t (264 gal.) for 5 to 7 days.

3 - For big Koi, the surgical knife is inserted under the raised scales, and the pus is drawn out carefully by pressing. After the iodine tincture is applied on the wound, bath treatment of 1 or 2 mentioned above is performed.

4 - Mix 0.1g of Oxolinic acid with food per koi weight 1 kg (2.2lb) and feed for 5 to 7 days.
Hole DiseaseThe muscle is exposed on the body surface as if the muscle is carved out by the spoon. The ulcer will be found in the abdomen, dorsal or tail section. They look like the hole is made. The section where anchor worms or fish louses are stuck mainly infects first. The affected section spreads gradually. The hole disease is developed in the section where the disease signs are hard to find such as the mouth, the base or tip of fins, and the abdomen.

Even just a single Koi gets the hole disease, the treatment is needed to all fish in the pond because the disease is contagious.
April to June.

Oct. to Nov.
The incidence of the hole disease will be higher with the water quality becomes worse. Maintain COD lower than 5PPM.

1 - Oxytetracycline with salt 5 kg /t (264 gal.) for 10 days

2 - Oxolinic Acid with salt 5 -6 kg /t (264 gal.) for 10 days.
3 - Mix 0.1g of Oxolinic acid with food per koi weight 1 kg (2.2lb) and feed for 5 to 7 days.
4 - Use Dryer to blow out the affected area for ten seconds. Repeat three times and put the medicine on the affected area. The treatment is performed for three days in a row. Be careful not to blow warm air into eyes or gills.
5 - Add aerobic bacteria

New Hole DiseaseDespite the absence of infections such as the anchor worm, roughly a single scale becomes red or bloodshot, the top of the fins hemorrhage and break-down during the early stage of this disease. In its progressed stage, the congestion proliferates. Moreover, the diseased fish display ulcers, drop-out of scale and loss of each fin, which are known as the typical symptoms of the hole disease.

However, the difference from the traditional hole disease is that antibacterial medicine do not work.

Moreover, the symptoms appear not only in the mouth, throat, gill covers, head, and face, but also in the section, where it is hard to find by looking down on the pond, such as the base of fins and the lower jaw.
All seasons especially when the season changes.The new hole disease is caused by non-typical Aeromonas salmonicida which is the resistant to the anti-bacterial medicine for aquatic organisms such as oxolinic acid and HCL-oxytetracyclin. Because the progression of this disease is faster and mortality rate is higher than the hole disease, it is very important to detect and treat the new hole disease in its early stage.

1 - Adsorb 0.05 to 0.1mL of 10%
Enrofloxacin liquid per day per 1kg (2.2LB) of fish
weight to 80 - 50% of pellet food of the
quantity usually fed. Feed for 5 to 7 days.

2 - Adsorb 0.02g of 25% Difloxacin soluble
powder per day per 1kg (2.2LB) of fish weight to
80 - 50% of pellet food of the quantity
usually fed. Feed for 5 to 7 days.

3 - Adsorb 0.5mL of 2% Florfenicol for
aquatic organisms per day per 1kg (2.2LB) of fish
weight to 80 - 50% of fish food usually fed.
Feed for 5 days.

4 - 0.2 - 0.4mL of 2.5% Enrofloxacin injection or 0.1 - 0.2mL of 5% Enrofloxacin injection per 1kg (2.2LB) of fish weight at a time. Injection should be made once per day for 3 - 5 days.

1 - Application of an ointment: The disinfectant for juman external wounds such as Iodine Tincture,
Povidoneiodine are good to use to disinfect the diseased hole part in seriously diseased fish. This should be done along with oral administration or injection

2 - Dryer treatment: blow out the affected area for ten seconds. Repeat three times and put the medicine on the affected area. The treatment is performed for three days in a row. Be careful not to blow warm air into eyes or gills.

3 - Scatter the aerobic bacteria such as Niigata Water Bio.


Koi Health Conclusion

Koi are exquisite animals and we have devoted our lives to these charming creatures. We hope you will share our expertise with koi admirers around the world and post your own comments below.

Please check back and use this guide often to enjoy a long life with your “living jewels”. If you want to keep learning more, here are some of our favorite parts of the website. To health and success!


Relevant Content

Learn our koi quarantining tank process

Tips for improving pond nitrogen cycle

The biological koi pond filter we use at the farm

How to make medicated koi food at home

Koi For Sale


1. *It is recommended that injections be performed under a vet’s guidance and/or supervision.
2. **Kodama Koi Farm &/OR Kodama Koi Garden is not responsible for loss of fish, damage to pond equipment, or other liabilities or damages incurred directly or indirectly from the use of the information contained in this guide (the “Koi Health Diagnostics Chart/Manual”).
3. ***Customer is responsible for performing any treatments or administering any medications indicated in this guide. Recommendations and instructions are made based on generally accepted circumstances & methods and may not apply to special or exclusive circumstances. Customer is ultimately responsible for observing & determining the situation and choosing the most applicable course of action.
4. ****Read all information, instructions and warnings carefully before using and administering any medications, especially injections. Those using this guide must also read all instructions and warnings provided by the manufacturer of, or printed on the particular medication/product label that he/she is using prior to using the medication/product. Customer is responsible for taking any precautions and understanding all warnings provided by different medications and products mentioned in this guide, or otherwise.