Treating unhealthy koi can be carried out in a number of ways.
The particular problem will often dictate the method used.
The simplest method is to add chemicals to the pond water.
In the case of an open wound, a topical treatment under anesthesia may suffice.
For systemic bacterial infection, it may be necessary to administer the correct antibiotic by injection.
Before using any medication, carefully consider the symptoms and carry out accurate water tests.
Symptoms displayed by koi in poor water can be similar to those of many diseases.
Do not overlook the effects of chemicals on the biological filter systems when deciding on a form of treatment.
If you add a medication to the pond, you will treat the entire population of fish, whether they require it or not.
Depending on the chemical used, the biological filter may also be damaged, resulting in rising ammonia levels.
Do not feed the fish while the treatment is in the water and carry out water tests, changing the water if necessary.
Also consider additional aeration, because many chemicals can cause deoxygenating of the water.
If a UVC is in use, switch it off while treatment continues.
This mode of therapy may be useful when the free swimming stages of parasites need to be killed, for example.
It may involve a second or third treatment administered a few days apart to ensure that successive hatches are caught.
A dip is given to a fish by placing it in a small bowl containing the required chemical treatment for a short period of time.
This may be the appropriate way to deal with a new koi harboring a known parasite problem before placing it into the pond.