Koi Health and Supplies » Parasites and Koi

Parasites are a real health issue when it comes to koi fish. The most common way koi fish contact parasites is from other fish.

Before a new koi is introduced to the pond, it is extremely important that the new fish be quarantined for 3 weeks. During this time period the koi should be treated for parasites.

Isolating a koi for 3 weeks in a quarantine tank, without treating the koi, is no assurance that the koi is parasite free. All that tells you is that if it has parasites, there are not enough of them to make it sick at this time.

If you do not have a separate quarantine tank in which to treat a new koi, then be very careful who you purchase your new koi from. Make sure the dealer is very conscientious about treating all their koi to make sure they are parasite free before they sell them. Do not take their word for it that they are parasite free. Ask them exactly how they treat their koi for parasites. If they are vague about how they treat the fish you would do well to assume the koi will have parasites and then make your decision as to whether or not to purchase the koi based on that fact.

The five most common parasites that affect koi fish are: flukes, costia, chilodinella, trichodina and ich. All of these parasites are microscopic which means you cannot see them without the aid of a microscope. The most common signs that you may have parasites are:

• Fish are flashing. Flashing is when a fish swims slowly near the side or bottom of the pond and then quickly swims off by first rubbing it's side against the pond wall.
• A fish is isolating itself from the other fish.
• One or more fish have stopped eating.
• A fish spends much of the time near the water fall gasping for air.
• Fish are sitting on the bottom of the pond with their fins clamped close to their body or are drifting in the pond with their head pointed upward or downward for several minutes at a time.
• Sores developing on the fishes body or fins.
• Fish are dying.

When selecting a treatment to rid koi of a particular parasite, you should always try to select a treatment that will effectively kill the parasite, while at the same time, cause the least amount of stress to the koi. Stress is a real factor that needs to be considered in treating koi.

Think of it this way. You can live and work around all sorts of germs and never get sick. Then things change at work and you are suddenly required to work very long hours for several days in a row. Now, when you can least afford it you get a cold. Why is that? It is because your immune system has failed due to the extra stress of working so much. It works the same way with koi fish. When they get stressed their immune system can begin to fail them and any hope for recovery will be slowed down, if in fact they recover at all.

An infestation of parasites can be very stressful to a koi. For this reason, it is very important when treating a koi with parasites to select a treatment that will not stress them anymore than is necessary.

For a printable treatment schedule click on the PDF file below.