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Anna, Pet Expert/Biologist
Category: Veterinary
Satisfied Customers: 11461
Experience:  40 yrs.: herps, pocket pets, rabbits, poultry, dogs, horses. Biology degree. Vet assistant.
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Do you treat koi? We have a large one who is on s side and

Customer Question

Do you treat koi? We have a large one who is on his side and can't swim, but he is breathing. We changed the water in his pond today and moved him. This happened after we put him back in his pond. The water is oxygenated and treated for chlorine.
Submitted: 1 year ago.
Category: Veterinary
Expert:  Joan replied 1 year ago.


My name is ***** ***** I have been a Vet tech for 30+ years and a fish keeper for 40+ years.

Have you checked the water Parameters?

What type of Test kit do you use?

Any abdominal swelling?

Red streaks in gills or fins?

What is the Ammonia, Nitrite, Nitrate and Ph?


Expert:  Anna replied 1 year ago.
Hello. My name is ***** ***** I'm a biologist with a special interest in fish. Joan has asked me to help. Besides what she asked you - I have a couple of other questions.Is there only one fish in the pond? If there are others, are they all right?Was the new water in the pond colder than what was in there before?Thank you.
Expert:  Anna replied 1 year ago.

I don't want you to have to wait any longer, so I'm going to go ahead and answer as best I can without knowing the additional information.

From what you have described, I believe your koi went into shock. There must have been some kind of sudden change between the old water and the new water. It may have been colder, which results in shock. As water stays in a pond the PH changes. Then when you change all the water, the pH goes back to whatever comes out of the tap. If that's a drop, pH shock results. Not getting all the chlorine out can also put a fish into shock. Sometimes, just being netted and moved around can do it.

Unfortunately, once a fish goes into shock, it is hard to save them. Don't add medications as that can make the situation worse. One of the best treatments for shock is an injection of a corticosteroid. Dexamethasone is often used with koi. You would have to contact an aquatic vet who makes house calls (many of them do). This link will take you to a directory of aquatic vets:

If you can't consult a vet, add pond salt at the rate of one teaspoon per gallon of water as a good first aid measure. You can also increase the aeration to help the fish. Temporarily set up a second pump with a bubbler or fountain. Don't change the water temperature again, as that just causes more shock. The water will gradually warm to what it was before. If you have a way to keep the fish moving, that will get more oxygen circulating through him. Don't feed him. These measures will be all of the first aid you can do on your own.

If you have more questions, just let me know. I hope your koi will be able to recover.


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