This is a disease which you really hope you will never experience as it is a notifiable condition. This means that once it is identified, you must inform the relevant authorities who may well take the step of killing your stocks and disinfecting your whole system. SVC should not be a concern for Koi keepers as long as they do not introduce stocks from the wild, especially if they live in a country where SVC is present. In fact it is illegal in most instances to take and move wild stocks without first discussing your intentions with the appropriate authorities.

It is also wise to avoid importing Koi from a region or country which is known to have SVC. That is why strict licensing is in place in countries where SVC is not currently a problem.

SVC will cause symptoms of ulceration on the skin of your Koi, as well as areas of reddening as the virus progresses. Sometimes these are accompanied by swelling of the belly area, and a loss of color in the gills. Surprisingly SVC will not result in heavy loses of adult Koi, but if you have young or small Koi and they are infected, losses of 100% may be expected.

If you are unfortunate enough to encounter this disease in your fish, it is vital that the correct authorities are notified. In most cases the laboratory carrying out the testing will do this as a matter of course. Although the subsequent culling may be hard to handle, try to remember that it is not only in your best interests but also those of the whole Koi industry.

Fish will usually survive SVC; but their carrier state is unconfirmed.

References: Manual of Koi Health by: Keith Holmes and Tony Pitham

Mortality is usually high. Unlike KHV, which seems to affect only koi and carp, this disease affects goldfish and other Cyprinids, including wild populations and bait fish. The USDA is exploring method(s) of controlling the spread of SVC in this country including quarantine, health certificates, importation guidelines, vaccinations, testing programs etc. Official guidelines should be available soon.