How to safely quarantine your new fish

One of your mantras when it comes to keeping Koi will be the Happy Koi Quarantine chant. It's fun and easy and everyone can learn it real quick...

Start by placing your your right hand with palm facing upwards. Slowly extend your arm to full length. Engage your vocal cords with a low 'ommm' chant. Snap your palm onto your forehead simultaneously uttering the word "Quarantine" in a short sharp fashion. Repeat.


We don't care where you buy your fish from. Even if they are from us you must follow quarantine procedures rigorously. This is because our fish may be carrying some bacterium or other that they are perfectly used to but which may cause massive problems with your pond fish, or vice versa.

One never knows!

Use your common sense when quarantining your new Koi - if it is winter there is no point in keeping the new Koi in warm water for two weeks only to chuck them back into cold water immediately thereafter - this will stress your Koi and cause problems that might otherwise have been avoided. If the water is cold when you buy your fish, keep them isolated until the main pond water's temperature gets to within 5 C of the quarantine facility.

Please understand that we take quarantining deadly seriously. In fact it is safe to say that without any doubt whatsoever we set the standards against which all others are measured when it comes to quarantining Koi that we sell. It takes us no less than 6 to 8 weeks before we release fish from a shipment from Japan.

This does not however give you license to ignore these procedures since the risk of KHV with any new Koi is a very real threat one and you are the last line of defense for your Koi collection.

Quarantine procedures:

1. Source a quarantine pond. Our Porta Ponds with a covering net are ideal temporary quarantine facilities.

2. Locate this pond as far away from your main pond as possible. This is to prevent water splash contamination. You do not want to discover your newly acquired fish has KHV and that you've splashed water into your main pond from the quarantine facility putting your entire collection at risk...

3. Based on the above, keep spare quarantine handling nets and quarantine vats. Also try keep the location of the pond secure and in as temperature stable a location as you can find. Your wife's parking spot in the garage is a great location.

4. Setup the pond one week before your new babies arrive. On the pond you will need a small filtration system to manage water quality. You can stock this filtration system with bio media from your main pond. A small submersiblem water pump is usually adequate to drive this filter system.

Feed your fish when they are in quarantine. It is important to maintain good water quality AND healthy fish - starving them when they are in quarantine is not going to benefit anyone - but keep a close eye on your water quality parameters. If you have to sacrifice a quantity of food on the alter of good water quality then so be it.

5. Oxygenate the quarantine pond with air stones. If you do have to medicate many medicines strip oxygen out of the water. And every Koi affliction is helped with well oxygenated water.

6. Add salt to a maximum value of 5kg/1000 litres. Use a salt meter to make sure you get this right - on a smaller pond it is easy to overdose with salt. Don't use the salt meter in your main pond without sterilising it first!

7. Add two or three fish from your collection to the quarantine pond a few days before the new additions arrive. This allows you to test the quarantine pond for any water problems and serves to introduce your new fish to any potential new bugs from your main pond. Ensure the pond net is securely attached. There is no greater loss than a Koi jumping out of a pond...

8. Introduce the new additions to the quarantine pond. Leave them alone for a day or so, with the net attached. We may have mentioned that there is no greater loss than having a Koi jump out of your pond... Not to mention how stupid you will feel afterwards.

9. Observe. If there is a problem with your fish, they will tell you in short order. Parasites will make their presence felt with your fish flashing or scraping themselves.

10. Do a 10% water change every other day. Ensure the filter system is operational. Feed carefully, sparingly but don't be stingy as we have mentioned above.

11. After three days do a microscope check (if you have one) for parasites. If you do not have a microscope get one. They are cheap(ish) second hand, certainly less than a halfway decent Koi, and they are fun to use. They also makes for great dinner conversation topic and your guests will all be in awe at your scientific abilities...

12. If the water temperature is in excess of 22 Celsius you will bring out KHV within about 10 days, assuming that the fish in question is also sufficiently stressed. If you suspect KHV you can send a gill clipping sample to MDS  (or any other lab that can test for KHV - the nested PCR test is the best) for verification. 

13. If after 3 or 4 weeks at 22 Celsius or higher if all is well with all of the fish, you may introduce your new arrivals into your main pond.

14. After a further 2-4 weeks you may reintroduce your bio-media back into your main filtration system - leave the quarantine pond running during this time just in case.

15. If the water temperature is below 22 Celsius, you will need to heat it to this temperature for at least 14 days to check for KHV. Pond heaters are common and relatively cheap. DO NOT SKIP THIS STEP.

If you cannot get your water temperature to 22 Celsius for at least 14 days, wait until you can before introducing your new Koi to your main collection. They may look healthy but if they are infected with KHV you will not know until the virus warms up and manifests itself. And by then it will be too late.

Don't take a chance with your precious collection of much loved, much fed and much enjoyed pets. It's simply not worth the risk.

PS & NB!!

As an addendum to this, many strains of bacteria will not present themselves within the first two weeks, even in warm water.  Whilst we endeavour to do our best to bring out as many of the resident 'germs' that Koi may be carrying, sometimes we do too good a job and manage to suppress these nasties from making their presence known.

Bacteria in particular are too small to be visible via microscope and even if this were possible it would not be easy to identify which bacteria it is that we are looking at. Bacterial outbreaks in a Koi collection crop up with monotonous regularity when new arrivals are added to your main collection without adequate quarantining in warm water if the quarantine period has not been long enough. Rather exercise your patience than your bank balance in medication costs...