Reputable koi dealers who support our operations typically quarantine all new koi shipments arriving from Japan for several weeks, if not several months before ever making these fish available for sale to their customers.  As a nonprofit animal rescue specializing in large Japanese koi fish, we complete a similar quarantine process for all rescued koi before making any of these fish available for rehoming. Without quarantine, hobbyists should understand they are not only risking the lives of these newly acquired fish but also the lives of their existing koi as well.  From parasite outbreaks to new pond syndrome, adding new koi directly to an established pond without quarantine is simply not worth the risk.

Many of the large koi fish entrusted to our care have spent many years within the same pond ecosystem.  Without any exposure to new pathogens, great care is often required to safely acclimate these koi to a new pond alongside existing fish.  Over nearly two decades, our volunteers have become quite proficient at completing this process.  Koi losses are exceptionally rare while these fish remain in our care.  To help ensure continued koi health in the future, we strongly recommend hobbyists complete a similar quarantine process before introducing any new koi additions to an established pond alongside existing fish.

A common misconception is that quarantine is not required if new koi appear to be healthy and/or if strict quarantine procedures have already been completed by your koi supplier.  Nothing could be further from the truth.  Getting chased around with a net and transported in a bag over an extended period can be very stressful for koi, which weakens their natural immune system.  This creates a very dangerous opportunity for parasites to strike.  Regardless of how healthy your existing koi may seem to be, these parasites and deadly anerobic bacteria exist in virtually any established koi pond.  Because they are not stressed due to recent handling and transport, your existing koi fish will often achieve a peaceful “co-existence” with the parasites and anerobic bacteria already present in your pond.  Introducing new koi fish, especially large koi will undoubtedly disrupt this balance. 

Since it is not possible to permanently eradicate all parasites nor deadly anerobic bacteria from any established koi pond, following strict quarantine procedures for all new koi additions is critically important to ensuring optimal koi health. 

What equipment is needed for koi quarantine?

A quarantine tank (QT) is a separate tank used to temporarily care for new koi additions before adding them to your main pond.  A QT does not need to be fancy or expensive.  In most cases, a used Rubbermaid 150-gallon stock tank would make an excellent QT.  In addition to a QT, you will also need a pump, filter, and aerator setup to keep the water in your QT clean and well oxygenated during the quarantine process.  Pond cover netting should also be used to help prevent new koi from jumping out of your QT during the quarantine process.  If screening for KHV and other common koi viruses, an aquarium heater should also be used during the quarantine process.       

Koi Quarantine Equipment List:

  • Holding tank
  • Pond Pump
  • Pond Filter
  • Pond Aerator
  • Pond Cover Netting
  • Aquarium Heater     

How long should I quarantine new koi additions?

We highly recommend a minimum quarantine period of 6 weeks for all new koi additions; however, we realize this is not always feasible for many hobbyists who cannot wait to add new koi to their ponds.  For this reason, we have prepared “quick” 21-day koi quarantine instructions to help encourage all hobbyists to complete some level of quarantine to help ensure optimal health for all their koi while avoiding potential fish losses.       

What koi treatments are needed during quarantine?

We consider 5 koi treatments to be absolute MUST-HAVE items for any serious koi keeper.  These critical treatments include (1) salt, (2) KOI BIO SHIELD, (3) KOI PRAZI or KOI PRAZI LIQUID, (4) potassium permanganate, and (5) KOI NITRO.

Essential MUST-HAVE Koi Treatments:

  • Salt
  • KOI BIO SHIELD
  • KOI PRAZI or KOI PRAZI LIQUID
  • Potassium Permanganate (PP)
  • KOI NITRO

Why do I need these koi treatments?

At proper dosage, salt alone can eradicate most common koi parasites all by itself.  Since over time many koi parasites have developed a resistance to salt, other koi treatments are also often required.  KOI BIO SHIELD helps to eliminate deadly anerobic bacteria, which often results in bacterial infections.  KOI PRAZI is the most effective treatment for salt-resistant flukes, including both skin flukes and gill flukes.  Potassium permanganate (PP) is an effective treatment for salt-resistant costia, another common koi parasite.  KOI NITRO is the most effective treatment for bacterial infections, which often result from parasite outbreaks.  

How do I prepare a quarantine tank for new koi arrivals?

Always add chlorine remover to your QT during partial water changes and use ammonia binders to prevent deadly ammonia spikes during the quarantine process.

Before adding new koi to your QT, be sure to add KOI BIO SHIELD to help eliminate deadly anerobic bacteria which can quickly result in deadly bacterial infections for new koi fish.

If you wish to screen for KHV and other koi viruses during the quarantine process, use an aquarium heater to maintain a consistent water temperature between 70°F – 72°F throughout quarantine process.

Salt Dosage Instructions:

We recommend maintaining a consistent salinity level of .04% in your QT throughout the quarantine process. To achieve .04% salinity, simply add 4 pounds salt per 100 gallons of water.  A digital salinity meter will allow you to easily monitor salt levels in your QT. 

KOI PRAZI Dosage Instructions:

Use 1 gram KOI PRAZI per 100 gallons water in your QT.  Mix KOI PRAZI well with water in a shaker cup. Once mixed, pour KOI PRAZI mixture directly into your QT.  KOI PRAZI will not impact your filter so there is no need to turn off your pump or bypass filter during KOI PRAZI treatment.

Potassium Permanganate (PP) Dosage Instructions:

Always have hydrogen peroxide readily available before using potassium permanganate (PP).  Use 4 ounces hydrogen peroxide per 100 gallons water to deactivate PP immediately.

Always turn off your pump or bypass your filter before starting PP treatment, because PP will kill all beneficial bacteria in your filter. 

Sufficient aeration is very important during PP treatment so keep your aerator running and closely monitor koi during PP treatment for any signs of stress.

If any issues are detected during PP treatment (i.e., fish jumping, swimming frantically, gasping for air, etc.) immediately add hydrogen peroxide to QT.

Use 1 gram PP per 100 gallons water. Mix PP well with water in a shaker cup. Once mixed, pour PP mixture directly into your QT.   During PP treatment the goal is for the water in your QT to remain purple for up to 4 hours. Once the water changes from purple to champagne, PP is no longer active, and it is safe to your filter back on.  After completing PP treatment, add 4 ounces hydrogen peroxide to instantly clear water.

How to Screen for Koi Herpes Virus (KHV) during Quarantine:

Koi Herpes Virus (KHV) and other common koi viruses typically reveal themselves when water temperatures are between 60° and 77°F.  KHV and other viruses also have an incubation period of only 7–21 days with higher temperatures almost certainly triggering an outbreak.  Maintaining a consistent water temperature of 70°F – 72°F during the koi quarantine process will allow hobbyists to safely screen new koi additions for these deadly viruses without putting their entire ponds at risk. 

“Quick” 21-Day Koi Quarantine Schedule:

  • Day 1: Complete KOI PRAZI treatment
  • Day 4: Complete PP treatment
  • Day 5: Complete 20% partial water change, add chlorine remover & ammonia binder
  • Day 7: Complete KOI PRAZI treatment, add KOI BIO SHIELD
  • Day 8: Complete KOI NITRO treatment (as needed for any bacterial infections)
  • Day 10: Complete PP treatment
  • Day 11: Complete 20% partial water change, add chlorine remover & ammonia binder
  • Day 14: Complete KOI PRAZI treatment, add KOI BIO SHIELD
  • Day 15: Complete KOI NITRO treatment (as needed for any bacterial infections)         
  • Day 17: Complete PP treatment
  • Day 21: Inspect all koi in QT then release to main pond if no issues are found      

Closely inspect all koi in your QT on day 21.  If no issues are found, then you may safely release your new koi into your pond.  If any issues are detected, then do not release new koi to your pond and extend quarantine period as needed until the issues are resolved.

What if I don’t have a QT?

If you choose to add new koi additions directly to your pond without first completing a quarantine process, then you must understand that your main pond now effectively becomes your QT.  This means you must treat it accordingly.  In most cases, simply adding salt to achieve .04% salinity in your pond is sufficient to help new koi recover from stress caused during handling and transport.  You should also treat your entire pond with KOI PRAZI for salt-resistant flukes and complete KOI NITRO treatment as needed for any bacterial infections.

Potassium Permanganate Bath for New Koi Additions (Instead of Quarantine):

Many hobbyists who choose not to quarantine new koi additions, instead opt to complete a quick PP bath for new koi fish before adding them to their ponds.  To complete a quick PP bath, simply add 1 gram PP mixture to 25 gallons dechlorinated water with aerator running.  Gently rub your hands all over fish, as this will help to remove any parasites.  Complete this process for 2 – 3 minutes, then move koi to another tank with clean dechlorinated water to remove the excess PP.  After this quick rinse, you can safely release new koi to your pond.  Again, be sure to have hydrogen peroxide readily available and monitor koi closely during PP treatment for any issues.