Koi diseases represent a critical problem for Koi lovers. The currently raging KHV is known to spread quickly, and there is a possibility of your own Koi being infected by the virus and could also result in affecting others’ Koi as well. Niigata prefecture is the birthplace of Nishikigoi. It is the world’s number one production district of Nishikigoi but also is the only prefecture in which there have been no reports of KHV and SVC. Niigata is the world leader in disease control, not to mention production volume and quality. We interviewed the Niigata Prefectural Inland Water Fisheries Experiment Station to ask about the breeders and government’s countermeasures towards diseases.

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Q: What is the function of the Inland Water Fisheries Experiment Station?  
A: Niigata Prefectural Inland Water Fisheries Experiment Station (hereinafter called Experiment Station) is a research institute under the control of the Niigata Prefectural Agriculture, Forestry and Fisheries Department.
The Experiment Station is divided into the Management Department, Aquafarming Department, Resources Department, and Pathology Environment Department and tackles individual issues such as 1) establishment of resource culture and certification technology 2) application of biotechnology 3) establishment of fish disease prevention technology 4) development and streamlining of aquafarming technology. Niigata prefecture has always dealt with KHV in a very strict manner, but the Chuetsu Earthquake caused the breeders to transfer their Koi among each other. We couldn’t let the Koi suffer infection by KHV on top of the damages they got from the quake, so we received a restoration budget from the government, and all applicants’ Koi were inspected. Afterwards, export guidelines were established. The guidelines state that all Koi must be inspected for KHV and SVC twice a year, so Niigata breeders are checked regularly. Each inspection costs more than 100,000 yen (approx. US$830); at the moment the prefecture offers subsidies for the inspection of SVC only.
Q: Are all of the Niigata breeders inspected for KHV and SVC?
A: I can’t say all breeders because the inspection itself is not enforced by law.
However, a 0 incidence of KHV and SVC within the prefecture shows that the breeders know that undergoing the inspection is for the benefit of both Koi lovers and breeders themselves. Corporation Aggregate Niigata Nishikigoi Conference, an organization with which a majority of the Nishikigoi breeders affiliate, has set rules that when transferring a Koi to other domestic farms it must be kept in a pool of water temperature of 18-23 C (64-73 F) for 3 weeks with a non-infected Koi provided by the Experiment Station. If the non-infected Koi stays healthy, the other Koi can be shipped out.
Q: Are the guidelines and the Conference’s rules different?
A: Yes, they are.
The guidelines were decided by the Experiment Station and breeders and belong to the prefecture and are geared towards exporting. The breeders who receive KHV and SVC inspection twice a year are registered in a list of the Agriculture, Forestry and Fisheries Department’s Fisheries Safety Bureau. When those registrants wish to export, the Experiment Station issues a Non-disease Certification after they pass a clinical check-up. While on the other hand, the Conference’s rules are for the domestic transfer of Koi. I believe Niigata is the only prefecture at the present to have its own guidelines.
Q: How should we prevent KHV?
A: It is extremely important to check the water source of ponds and to avoid transfer of Koi.
KHV is a very strong virus; after leaving animal cells, it can live in water for approximately one month, so there is a risk of water becoming the transmitting agent. At the Nogyosai, we pay minute attention so that not even a drop of water from the breeders’ ponds is mixed with other water tanks. It is safe to use well water or spring water, but please avoid irrigating from the river because there is a possibility of infection if water upstream has been contaminated by KHV. What you need to look out for the most is the transfer of Koi. KHV will most certainly outbreak at water temperature of 20 to 25 ? (68 to 77 F) but at 30? (86 F) the bacteria within the body become extinct and that Koi will be immunized. But that Koi is already a carrier at that point, so if you raise other Koi in the same pond, they will be infected with KHV. You therefore should not put in a Koi if you don’t know where it came from because as healthy as it looks, it might be a carrier. Koi lovers often keep others’ Koi or pass them on to others, but I believe such actions should be avoided to prevent further spreading of KHV. As I mentioned earlier, Koi coming from Niigata breeders are safe. However, I unfortunately cannot deny the possibility of them being infected by KHV during the transportation process. It is a good idea to check your dealers’ countermeasures and testing systems towards Koi diseases.

Niigata prefecture takes full pride as the birth land of Nishikigoi and adopts thoroughgoing measures in preventing fish diseases. There have been rumors of outbreak of KHV or extinction of Koi after the earthquake, but they are all groundless false information.
We in Niigata will keep the 0 incidence of KHV and SVC and will make efforts to provide all Koi lovers with the safest and healthiest Koi. We look forward to receiving your support.