Why quarantine Koi?

Why quarantine koi before introducing them into your pond?

  1. The quarantine process will allow the new koi time to rest and recover from the stress of handling, moving and transport. Stress weakens its immune system and a koi with a weakened immune system is highly prone to disease and parasite attack. Quarantining new koi fish gives them time to bounce back and get back into tip-top health.
  2. The koi quarantine period allows the new fish to become accustomed to the water parameters of its new home and to the pathogens living there. As with all living creatures, we’ve all been exposed to various pathogens.  The question isn’t IF the koi has been exposed to pathogenic bacteria, but how high or how low the level of the pathogenic bacteria has been.
  3. You don’t want to expose your other koi to the pathogens on the new Koi should there be an outbreak of some sort. The segregation of all new arrivals will provide ample time for any pathogens and parasites to cycle and become apparent. In the unfortunate event that this new fish becomes ill with disease or parasites it will be much easier to deal with the situation in the contained space of a quarantine tank rather than in your entire koi pond.

Quarantining new koi fish is not a simple task. If not conducted properly then you can increase the stress on the new fish and do more harm than good. Below is a list of what you need…

  1. Quarantine Tank – Use only plastic, rubber or PVC products. Galvanized tanks can be harmful to fish. Use a tank of sufficient size to hold the fish comfortably. A 100 gallon tank can quarantine 4 koi of 10” size. Heavy-duty collapsible quarantine tanks can be purchased online.
  2. Tank Heater – A submersible 300 watt heater should do the job. Maintain a water temperature in the 74°-78° F range throughout the quarantine period.
  3. Bio Filtration with Pump – Every quarantine system will need a bio filter and circulating water pump. The pump should be large enough to circulate the entire volume of the tank every 30-45 minutes. The bio filter can be a little tedious to get going; an adequate bio filter can take up to 3 weeks to become aged. To jump-start the process you can place some extra sponge type filter media your koi pond’s filter for several weeks. Then transplant the sponges now seeded with good bacteria into the quarantine system filter approximately two days prior to introducing new koi to the quarantine tank. Be sure to use de-chlorinator before installing the pre-seeded filter media as any chlorine in the water will kill off the bacteria and undermine your efforts.
  4. Aeration Device – All fish need oxygen and so does the bio filter. Keep your aeration pump running with at least one air stone on the bottom of the tank at all times. Any span without aeration is asking for trouble. 
  5. A Lid or Cover – Koi will jump in attempts to flee unfamiliar surroundings. You should have a weighted net large enough to cover the entire tank. Many koi have been lost by jumping through the smallest area left uncovered and unattended. Another option is to build a sturdy wooden frame and staple plastic mesh onto the frame. You should not use clear plastic or glass as a cover for quarantine tanks because they will increase the temperature of the water. Your cover should allow for fresh air yet protect your koi from predators.

Tips on Quarantining Koi

  • Do set up your quarantine tank at least 1 week prior to new koi arrival. Establishing a bio filter can take up to 3 weeks.
  • 4 -6 weeks is about the right length of quarantine
  • Do not feed fish in the quarantine tank for the first two days. Then offer very small portions of food once per day.
  • Be sure to monitor ammonia level with a test kit and stop feeding and perform a water change if the ammonia begins to creep up.
  • DON’T use chemical treatments UNLESS you have a specific reaton and you know what you are doing.
  • Salt is probably the safest and most effective additive for use in the koi quarantine tank. Salt will kill or slow down most parasites and ease the stress level for your koi. Salt concentration should be maintained at .3 ppt, or 3 lbs. per 100 gallons of water. For therapeutic application it is recommended to use only non-iodized salt. Remember to add salt with every water change.
  • Monitor water quality. Test for ammonia, nitrite and pH daily. Purchase a test kit or new supplies.
  • Perform regular water changes of 10-15% every day.
  • Provide a hiding place for koi. A submerged piece of PVC will make a good hideaway. Float a piece of Styrofoam on the surface; it will provide shade as well as protection.
  • If you suspect Parasites, do skin scrapes on the third day of quarantine and 3 days before the quarantine period ends.
  • Maintain water temperature between 74°-78° F.
  • Don’t quarantine a single fish unless it cannot be helped. Koi are very social and will sulk when isolated which can increase stress.
  • Don’t use the dip or concentrated bath method to administer any treatment to new koi.
  • Don’t allow faeces or debris to build up in the quarantine tank. Use a siphon or wet-vac to remove any accumulating debris.
  • Don’t ignore the fish while in quarantine. It may be better to put the new fish directly into your pond if you are not going to monitor its health, maintain water quality, etc.
  • Run an aerator 24/7. Any time without a bubbler can induce stress or become fatal.