Important Facts of the News
- Koi herpesvirus (KHV) outbreaks detected at multiple sites in England and Wales in 2025.
- KHV is a listed fish disease in the United Kingdom affecting all common and ornamental carp (Cyprinus carpio).
- Infected fish often show signs when water temperature is between 16 to 28 °C.
- Typical symptoms include necrotic white or brown gill patches, rough skin with sloughing mucus and sunken eyes.
- Anyone suspecting KHV or carp deaths must report to the Fish Health Inspectorate (FHI).
- There is no risk to public health from KHV.
- Sites with confirmed disease must follow a mandatory monitoring programme and statutory controls.
- Movement of aquatic animals, eggs and gametes into, out of or within a designated area requires FHI written consent.
- Dead fish and related waste must be disposed of as Category 2 animal-by-product waste according to local Environmental Health rules.
- All requests for FHI consents require a minimum of 5 working days’ notice.
Overview of the 2025 KHV Situation
The Fish Health Inspectorate has identified cases of Koi herpesvirus infection at several locations in England and Wales during 2025. The disease is formally recognised as a notifiable fish illness in the United Kingdom and can cause high carp mortality. Both ornamental and common carp varieties are vulnerable.
Symptoms to Watch For
Carp affected by KHV tend to show clinical signs most often when water temperatures fall between 16 and 28 degrees Celsius. Fish keepers and anglers should stay alert for necrotic gill tissue that appears white or brown, coarse skin surfaces with peeling mucus and noticeably sunken eyes. Any suspicion of infection or unexplained carp deaths must be reported to the FHI without delay.
Public Health and Safety
KHV poses no risk to human health. The disease is limited to carp species and carp hybrids.
Monitoring and Controls at Affected Sites
Once KHV is confirmed at a site, a statutory monitoring plan is enforced. Inspectors carry out visits to check for ongoing infection and verify that required controls are being met. These measures aim to prevent the virus from spreading to nearby fisheries, lakes or ponds.
Key Restriction Measures
Controls applied to designated areas include strict movement rules for live fish, eggs and gametes. Transport of these items into, out of or within the controlled area is only allowed after written approval from the FHI.
Any dead aquatic animals or related by-products from the designated site must be disposed of using an approved Category 2 animal-by-product method that complies with local Environmental Health guidance.
Site operators must promptly alert the FHI if fish deaths return or if the issue spreads to other waters or facilities inside the controlled zone.
Changes Requiring Advance Permission
Planned physical alterations to the affected site also require prior written consent from the FHI. This includes changes to site boundaries, number or size of water bodies or the intended purpose of the location. A minimum notice period of five working days is needed for requests related to these permissions.