People often ask us about how to handle new bought koi into their environment, especially those who haven’t experienced in fish quarantine. You can use this guide to properly introduce new koi fish into your pond using the proper quarantining, pond care, and water quality control methods for good husbandry in koi care. Based on our Japanese breeders and koi farm, these techniques are what work best when receiving Ben’s Koi Farm’s Koi fish but are also good tips for any koi pond owner adding more koi to their pond.

Adding new koi to your pond is exciting and fun but should be approached with caution. If you have not added any outside koi in over a year then take extra precautions mentioned in this article below. The natural instinct for Nishikigoi is to coexist with others and to bring peace into a home, which is part of their attraction along with their beauty.

Before You Receive Nishikigoi

A necessary tool for all koi hobbyists and owners that should be prepared before the fish come to your place is a separate quarantine tank. Basic supplies needed for a quarantine tank consists of 100-300 gallons tank or blue show vat, net cover for the tank, small pump and filter, air pump, pond heater, salt, and thermometer.

It is strongly recommended that every koi purchased should be quarantined before adding to your aquarium or pond. That is because it is possible that newly purchased Nishikigoi carry parasites, bacteria, fungus, and other illnesses despite all the best efforts done to eliminate them. Koi fish tend to become extremely stressed and exhausted while in transport from the farm or breeder to the owner. That’s why we cannot just put the fish directly into our pond and need to quarantine and observe the condition of the fish as well.

Prepare the quarantine tank depending on the size of your koi. We recommend 100-300 gallons, blue show tanks are OK too. Maintain a water temperature of 24° C or above. If working with a smaller tank, 1-2 aquarium heaters will work to achieve that.  Ideally, the quarantine tank should have a filtration system as well, but sound aeration from an air pump is acceptable. Add salt to the tank until it is 0.3% concentration (3 pounds of salt per 100 gallons of water)

When You Receive Nishikigoi

Pet supplier usually send the fish using cargo or train packed with styrofoam box or send it by themselves if the supplier is near your place. When you bought fish from 2 or more different fish supplier, pay extra attention when you put them together in the quarantine tank. the steps to do are float the plastic bag for 20-30 minutes before releasing fish to the tank to make the water temperature of the plastic bag equal with the environment. After that, you can put some water from your own tank to each plastic bag and wait few moments again to prevent stress to the fish. the next step when the water from your tank mixed with the water from the fish supplier is, lift the fish and move the fish to the quarantine tank without pouring the water from the plastic bag in order to avoid the bacteria clash from different water sources.

What To Do After You Receive Nishikigoi

It is recommended to keep and treat newly purchased koi fish in a separate quarantine tank for at least 21 days before introducing them to your pond or aquarium to reduce the risk of disease while giving them time to adjust with the new environment. Observe them and see if they develop any problems. If you working without a filtration system, do partial water changes every 2-3 days of about 25% level of water and then add salt to adjust accordingly. Feed your Nishikigoi with digestible koi food and check nitrate & ammonia level every day.

Please note – If you have not added any new koi in over a year, it is particularly important to quarantine both new and existing Nishikigoi. It is highly recommended to introduce one of your old Nishikigoi into the quarantine tank after the new koi has gone through the normal procedure to ensure that all koi in your pond can coexist in the same water conditions and ecosystem. We also suggest raising the salt level to 0.5% in this scenario.


That is all about how to handle new koi after receiving from the breeder or pet supplier. Hope you guys can understand and apply this method easily.

If there any questions, please kindly comment on the comment section below.



Leave a Reply

Your email address will not be published. Required fields are marked *

11 + 17 =