After koi fish gets sick, it should be isolated first. Isolation has two advantages. On the one hand, it prevents diseases from spreading and causing other healthy fish to get sick; On the other hand, it prevents sick fish from being bullied. In addition to isolation, stop feeding sick fish. Usually, after getting sick, the appetite of koi fish will drop, and it will pollute the water body and lead to the deterioration of water quality, which is very unfavorable to its recovery, so it is necessary to stop feeding.

In the early stage of koi disease, 3 kinds of treatment should be used. The so-called old three kinds refer to changing water, heating up and adding salt. Changing water can improve the water environment as soon as possible, usually every other day, about a quarter of each time. Heating up can promote metabolism, let fish discharge harmful substances and accelerate self-healing. Salt can change the osmotic pressure of water and reduce the infiltration of water, thus preventing bacteria from invading.

If koi fish is seriously ill, it can no longer be treated by the old three samples alone, so it needs to be soaked with drugs at this time. There are many choices of drugs, commonly used is yellow powder, but it is best to prescribe the right medicine according to the condition, and gentamicin, oxytetracycline and other drugs can be used. Medicated bath must pay attention to the concentration. Once the drug is overdosed, it will not only fail to achieve the therapeutic effect, but will produce drug harm.