Viruses & biosecurity
KHV: koi herpesvirus
KHV is a serious viral disease of common carp, including koi. A healthy-looking fish or a clean skin scrape cannot establish freedom from it.
Signs to take seriously
Gill damage, sunken eyes, altered mucus and lethargy can occur. These signs overlap with other problems; laboratory testing is needed. Several ill fish or unexplained losses warrant prompt professional attention.
What to do
Do not move or sell affected fish, share nets or transfer pond water to another system. In England and Wales, report suspected KHV immediately to the Fish Health Inspectorate using the official contact details below. Follow its instructions.
What a guarantee means
Source documentation and testing reduce uncertainty; they do not replace careful quarantine or prevent later exposure. A negative parasite scrape is not a viral test. Do not attempt to cure suspected KHV by heating the pond.
Sources & further reading
Original WakeyKoi wording, informed by the references below. Linked clinical resources explain the evidence and their scope; they have not reviewed or endorsed this website.
Related guides
Educational guidance cannot diagnose an individual fish. Breathing distress, severe injury or unexplained losses need prompt professional assessment.