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If you have a koi, pond or fish problem, this site takes you through twenty easy questions and at the end you know what you need to fix in your pond to create restored Koi health.



Koi Behavior of  Diseases or Disorders

+ Koi setting on the bottom lethargically
+ Koi laying over
+ Koi hanging at the surface
+ Koi gasping at the surface
+ Koi flashing, jumping and scratching
+ Koi swimming head down
+ Koi just won't eat
+ Koi is isolating itself from the rest.
+ Koi has kinked back, spastic swimming
+ How to warm your koi up for any treatment

+My Koi are setting on the bottom lethargically

Normally this would be a symptom of a mild parasitism or more likely, poor water quality. Make sure you examine the pond with our PondCrisis programme to see if there's anything amiss in your pond.

Koi setting on the bottom normally occurs when nitrogen is accumulating in the system, in the form of Ammonia, Nitrite or Nitrate. Test your pond water now!

If pond water changes are too infrequent (less than twice per month) the pond water may be foamy and yellowish, which all by itself, sends your koi to the bottom in misery. Water tests recommended first.

If your koi are without any other symptom, a major pond water change should perk them up. If not, and if your pond water quality is impeccable, Koi on the bottom are suffering with parasites.

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+ My Koi are laying over

BehaviorLaying over is nothing but severe fish stress. There are hardly any exceptions. Normally when your koi fish are laying over, something is TERRIBLY wrong in terms of your koi pond water quality or parasites are working them over too. I've seen most of the Laying Over in icey winter water. But the most memorable case of "laying over" I ever saw was with Trichodina. If the fish weren't flashing and scratching they were laying on their sides. When you'd disturb the fish they would pretend everything was okay and swim around for a time. If I had fish laying over, I'd make sure my pond water got into the low seventies as fast as safely possible, and then I'd use a combination of Terminate and Aqua Prazi to put most of the ciliates and the Flukes out of their misery. If I could, I'd use a scope instead and determine what the fish actually HAD before shotgunning.

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Warming a Koi up:

Koi in winter ice pond water sometimes need to be warmed up for various treatments or to rescue them from genuine cold water illnesses such as Laying Over. To avoid shock, the fish should be put in a very large vat of this icy pond water in your garage. I repeat, you're going to use the icy pond water from your pond, that the fish is used to. This vat should be at least 75 gallons in size or the temperature will equalize too rapidly and kill the fish. They cannot climb up more than 10 degrees F per 18 hours without serious stress or death. Let the vat slowly warm to garage temperature using the ambient room air.

USE NO HEATER. Do nothing to accelerate the warming process. It's meant to be slow! As the fish warm up, they will become more active. Make sure the vat is covered. Once they have been in the mid sixties for 24 hours, you can raise the temperature with a commercial aquarium heater or a paint-bucket warmer, by five degrees per day til in the low seventies.

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+  My Koi are hanging at the surface

Koi which hang at the surface of your pond water are usually showing a stress response, often to a too-low pH. You can easily test your pond pH with a commerically available test kit. Be sure to choose a Wide Range test kit because readings above or below a narrow range will be meaningless. If your koi are hanging at the surface of your koi pond, you should consider some decline in your pond water quality, a decline in dissolved oxygen, a decline in pH, or a harmful parasitism which is reducing oxygen transfer at the gill - causing your koi to hang near the better-oxygenated surface.

If I had koi hanging at the surface, I would recommend a major water change with dechlorinator to both refresh and cool the pond down. Cooler water carries more oxygen. The water change can decrease a bacterial or parasitic burden. Then I would consider salt and Aqua Prazi as a reasonable shotgun therapy if parasites were suspected. Better still, use a microscope and know what is wrong with your koi fish.

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+ My koi gasping at the surface.

Most of the koi you actually see GASPING at the pond water's surface are having an oxygen transfer issue. Most folks ASSUME that there is not enough oxygen in the water, and of course this would be the first thing to rule out. If the pond is warm (78 DF or higher) and there's no major splashing or water movement (water fall is ideal) then a low dissolved oxygen is a reasonable thought.

Past that, oxygen transfer can be impeded by poor pond water quality, Ammonia accumulations, a low pH (cure) causing excessive sliming of the gills, or a parasitism that damages gills and impedes oxygen transfer.
If I had koi gasping at the surface I would check the pond water temperature and make sure it was below eighty degrees F as soon as possible. I would test my pond water for any accumulated toxin that might hamper gill function. I would seriously consider a massive pond water change and then a low level salting regimen.

Any case of fish illness can be simplified by KNOWING what parasites might be present. You would need a microscope for this.

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+  My Koi are flashing, jumping and scratching:

Normally a koi "scratches" once or twice per day. So if you saw one of your koi scratching every hour you would know something was irritating its skin. That "something" can be as simple as a change in the pH  or alkalinity of the water. Temperature changes are sometimes associated with flashing behaviors. Finally, parasitic infestations can cause flashing behavior, including Trichodina (cure), Flukes (cure), Anchor Worm and Fish Lice. (cure)

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+ My koi are swimming head down

I've never seen a koi exhibiting this behavior that did not end up manifesting a bacterial infection. I believe the head down posture is an accurate early warning sign that bacteria are assailing the koi's system. I would highly recommend the fastest, earliest possible injection of antibiotics and the institution of a medicated koi food feeding regimen. antibacterial bath  has really changed everything as it replaces injections for those who are afraid to do them. Salting the pond is also a good idea.

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+  My Koi just won't eat

A koi that just won't eat is probably in suboptimal pond water conditions. Ammonia may be accumulating, pH could be sagging, or both. Other parameters may be out of line. I would recommend a test of all pond water parameters, as soon as you can. If a major pond water change has not been done in recent history, I would execute a major 70% pond water change immediately. Make sure that if you're using municipal water for replacement that you dechlorinate the water. If the fish still will not eat, consider salting the pond or using Terminate. Or, check your koi for parastes under a microscope. This will refine your treatment strategies..

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+ My Koi is isolating itself from the rest.

This is just the worst thing you can ever see when you look in your koi pond that was once healthy. Probably, you added some new koi without quarantine. Now, you look in koi pond and one or more koi may be isolating themselves away from the rest. These are the sick koi. No koi, not even small koi, will normally isolate themselves from the rest of the koi pond. If you see a little guy hovering behind the skimmer, the only good news is that the koi is giving you a warning sign that it's sick. Haul out the koi and examine it closely, including, if not especially the gills! Perform all water tests on the pond and then perform a major water change if one has not been done in the last four weeks. Make sure that if you're using municipal water for replacement that you dechlorinate the water. If water quality checks out fine, and the fish are still isolating, you should either diagnose the problem with a microscope or perhaps consider a lightweight salting regimen.

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My Koi has a kinked back - Spastic Swimming.

If this has shown up suddenly, there are several possible causes, but usually this is caused by a lightning strike or electrical discharge into your water from a damaged electrical appliance. Sometimes you get lucky and the appliance causing the trouble identifies itself by "kicking the breaker" and is off when you simultaneously discover you koi with this symptom. When you see a koi with a kinked back swimming spastically, don't dispair. If they have been electrically shocked, here's their prognostic information (chances): 

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Action Items

+ In almost any case, water testing is indicated FIRST
+ Finding medicated koi food is sometimes tricky. People sell Romet feed as their own "brand" of medicated koi food. It's not as effective as it was in the early nineties. Medi-Koi is recommended highly.
+ Improving oxygenation can NEVER hurt.
+ Changing a considerable amount (70-80%) of your koi pond water is, in most cases, a highly commendable FIRST action, before applying any other remedy.

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