koi health care

The goal of all good Koi Keepers should be to maintain a healthy collection of thriving Koi. Unfortunately most koi do not die from natural causes. In the long run you will not be successful with poor husbandry practices and pond design flaws

Now that there is so much information readily available on fish care, there is really no reason not to learn from other peoples experiences and not at the expense of your fish Remember, your fish are relying on you to provide for them. The old adage, "An Ounce Of Prevention is Worth a Pound of Cure" is so true in this hobby
  • These gills have been burned with a medication or bad WQ
  • We diagnosed this poor Ochiba with TB due to the bent spine and sores
  • This koi is in rough shape. Looks like parasites and bacterial issues

Threats - Parasites, Bacteria, Fungus and Viruses

Pathogens are divided into 4 categories. Parasites include microscopic single celled flagellates and ciliates to visible crustaceans like Anchor Worm. Bacterial problems like aeromonas and pseudomonas can bring down a fish quickly. Fungal issues include Saprolegnia, or "Sap" which affects dead tissue exhibiting a white tuft like appearance. Viral problems range from the harmless koi pox to the deadly KHV which will likely kill all of your fish

The most important concept is that a proper diagnoses should be obtained before administering medications. Many Meds can be deadly if overdosed and should only be used when you know your ponds volume

Treatment Options for parasites


Does not harm your filter and will kill flukes in about a weeks time. The only negative is the high cost


Broad spectrum treatment which needs to be dosed correctly. Negligible impact on the filter and very effective at eradicating protozoa


Kills the likes of the larger crustacean parasites like Anchor Worm and Fish Lice Debride

Koi Health Lecture from the AKCA 2009 Seminar in San Diego

Download an mp3 version to listen to on the go

Treatment Options for Bacterial Problems

Bifuran Powder

An excellent powdered bactericide which does not harm nitrifiers in your filter - giving it a big advantage over PP

Potassium Permanganate

PP is not a selective bactericide. Must be handled with care and is suggested for experience keepers only. Utilizing an ORP meter is really the proper way to go when using potassium

Debride Medicated Ointment

Should be applied to seal wounds once they have been cleaned with Povidone-Iodine Ointment. We find refrigeration creates a stickier ointment


An excellent natural wound treatment that helps heal injured fish and grow back finnage. Its important to realize that you need to kill the bacteria or offending parasites before wound treatment will truly become effective

Debride Medicated Food

Antibiotic foods help rid the fish of systemic bacterial infections and should be fed as lesions appear or look like they will appear

Tricide Neo

A powdered bath which is mixed with distilled water to create a strong bactericide which fish are placed in for up to 5 minutes daily for up to 7 days in a row


In more serious cases of ulceration and systemic infection, injections are often the only hope for the fish. Antibiotics to consider are Baytril, Amakacin, Chlormaphenicol and Azactum. Baytril is a very safe drug, I find Amakacin to be very effective, Chloramphenicol can be deadly to humans [Grey's disease] and we have not tried Azactum [which is very expensive]
  • Bacterial issues can cause extensive damage and stubborn to cure
  • This ulcer is not too deep and is starting to heal
  • A great method to examine a fish is to put it into a plastic bag