Viruses & biosecurity
SVC: spring viraemia of carp
SVC is a serious viral infection that can affect carp and other susceptible fish. It needs official investigation, not a guessed pond treatment.
What keepers may notice
Affected fish may become lethargic, lose balance, develop swelling or bleeding and gather at pond margins or water outlets. Cooler seasonal temperatures can be associated with outbreaks; symptoms alone are not diagnostic.
Act promptly
There is no curative treatment for SVC. Avoid moving fish or sharing equipment. Report suspicion immediately to the Fish Health Inspectorate in England and Wales; follow its sampling and movement instructions.
Before bringing fish home
Keep purchase and origin records. Ask what the supplier’s documentation covers, and keep new arrivals separate where possible. Record illness and losses rather than assuming the problem has disappeared when one fish improves.
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.