Quarantine Your New Koi

The purchase of a new koi is an investment in expanding your koi hobby. Adding the new arrival to your pond is super exciting, as you want to see the new koi swimming with the rest of your koi. But introducing this new koi to your pond without proper precautions could brew trouble.

First, this new koi needs to acclimate to your water parameters, as even a shift in the pH could cause issues. Does the new koi have any parasites that could spread to your koi?

Although dealers have performed proper quarantine of the new koi imported into their facility, koi hobbyist should still do their due diligence in protecting the investment of their new koi as well as the existing koi in the pond.

Setting Up a Quarantine System

Setting up a quarantine system and having it running consistently is always best, but not everyone has that capability.  So, for that reason having the basic quarantine system ready to go is essential in protecting your investment.  A quarantine system will also depend on the size of your koi, some smaller koi can be placed in an aquarium set up, where they have room to swim around.  A plastic container is also another option, there are some koi quarantine setups on the market that even come with filtration systems.  Just make sure whichever holding tank you choose you secure the top of it tightly with netting as koi will tend to try to jump out the tank, so all sides of the netting should be secured. 

All new koi should be quarantined for a minimum of 4 – 6 weeks. 

Minimum size recommendations are 100 – 500 gallons, but it will all be dependent on where you can set it up. The garage is a good start as there is shade and you can check on the koi periodically.  It is best to fill the quarantine tank with your existing pond water because adding new tap water may have chlorine and will need to be treated.  The quarantine tank should have an operative cycled, filtration system, as well as oxygen such as having an air stone.  Make sure you add a “canary” koi from your pond system.  This is so that you can see if that “canary” koi starts to exhibit strange behavior, such as isolation, or not eating, you know that the new arrival koi has some issue.  Outside make sure it is not in full sun as that will heat up the water and stress the koi. Protect the koi from any predators that could get underneath the netting.

Photo Courtesy of Kodama Koi Farm

Recommended water temperatures are 74°F to 76°F, if in the winter buying a submersible heater can control the temperatures.  The reasoning for this temperature range is to check for certain parasites that are more active in warmer temperatures. 

Adding salt at the rate of 2.5 lbs per 100 gallons will create a 0.3% salt solution that will help soothe the koi. DO NOT drop a bunch of koi treatments in the water, many of those will coat the koi gills causing the koi do have respiratory issues.

TEST your quarantine water parameters daily (ammonia, pH, nitrite, nitrate), ammonia can spike quite rapidly in the right environment and that would kill the new koi fast.  In the first few days, I would recommend no feeding, let the koi acclimate to their new environment, then feed lightly, and make sure they eat the food; any uneaten food should be removed right away as this will create a poor water quality issue. 

Don’t forget to perform weekly water changes, at least 25%.

Advanced hobbyists also recommend performing a gill snip and scrape of the koi’s body and check with a microscope for any parasites.  If parasites are detected, then treat accordingly for that particular parasite.

Items needed for quarantine system:

  • Tank 100 to 500 gallons
  • Tank cover netting
  • Pond filter
  • Air pump with air stone
  • Pond thermometer
  • Salt meter
  • De-chlor such as Cloram-x
  • Water test kit for testing parameters
  • Salt for koi pond use such as water softener salt (no added chemicals)

By being prepared with a quarantine system set up you are protecting your new koi and existing koi from any problems because treating a sick koi in a small tank is much easier than treating your whole pond system.  Happy koi keeping!