Changes to KHV disease controls in recreational fisheries
From June 2026, the Fish Health Inspectorate’s (FHI) approach to managing Koi herpesvirus (KHV) in recreational fisheries in England and Wales will change.
This reflects our established proportionate and risk-based approach to aquatic animal health controls and is informed by evidence demonstrating the endemic nature of KHV in wild fish populations and that statutory disease controls do not materially influence pathogen spread.
Importantly, this change does not affect the legal requirement to report suspicion or confirmation of KHV to the FHI under the Aquatic Animal Health (England and Wales) Regulations 2009.
How suspected cases will be managed
All reports of suspected KHV will continue to be assessed, recorded and monitored by the FHI.
Where the species affected, water temperature, clinical signs and mortality patterns are consistent with KHV disease and there are no grounds to suspect another listed or emerging disease:
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the FHI will not routinely undertake statutory sampling; and
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will not routinely impose statutory disease control measures at recreational fisheries.
Instead, the FHI will:
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maintain ongoing contact with the fishery operator and relevant partners, including the Environment Agency;
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provide advice on appropriate biosecurity measures; and
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monitor for any changes in the clinical picture.
If the disease risk changes, or there is suspicion of another listed or emerging disease, the FHI will take further action. This may include:
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an investigation to determine the introduction and spread of the disease
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collection of samples for testing at the relevant National Reference Laboratory at the Cefas Weymouth Laboratory
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the application of disease control measures where appropriate
Investigation of KHV disease outbreaks and controls will continue to be applied at authorised aquaculture production businesses (APBs) and sites involved in fish movements, such as fish farms, importers, wholesalers and KHV approved compartments.
Fishery operators may choose to undertake private diagnostic testing to support their own site management decisions. The Environment Agency may also undertake sampling in support of its fisheries management and regulatory responsibilities, including fish mortality investigations at their National Fisheries Laboratory.
Any suspected or confirmed cases of KHV, including relevant diagnostic results, must still be reported to the FHI.
Roles and responsibilities
The FHI is responsible for statutory disease surveillance and control of listed aquatic animal diseases, and for leading the response to suspected or emerging aquatic animal disease threats.
The Environment Agency (EA) is responsible for the management of freshwater fisheries, playing a key role to maintain and protect the health and resilience of fisheries, within its fisheries management remit in England. During a KHV outbreak, the EA may:
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work with fishery operators to provide advice and guidance on management practices; and
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consider, on a case-by-case basis, whether to authorise activities such as fish movements using its statutory regulatory powers.
These decisions are based on fisheries management considerations and are separate from, and do not replace, the FHI’s statutory responsibilities for disease control.
Why the approach is changing
Over time, Cefas scientists and epidemiologists have undertaken multiple reviews of KHV controls, drawing on more than 15 years of outbreak investigations and epidemiological analyses.
These reviews consistently show that:
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KHV is endemic and widespread in recreational fisheries in England and Wales
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outbreaks occur regularly and are influenced primarily by environmental conditions and stress, with good fishery management and biosecurity practices helping to reduce likelihood and impact.
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affected fisheries present a low risk of onward spread, due to limited live fish movements
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statutory controls at these sites have not demonstrably reduced disease frequency or spread
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the virus persists in sub-clinically infected carp populations in recreational fisheries and wild populations, with carrier fish often showing no obvious signs of disease
Taken together, this evidence shows that applying statutory disease controls at recreational fisheries does not materially affect the overall epidemiological situation and spread of KHV.
On this basis, Defra has endorsed a revised, evidence-led and proportionate approach to statutory disease control in recreational fisheries.
This approach ensures that:
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regulatory effort is targeted where it provides clear benefit to aquatic animal health
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fishery operators are supported through advice and good practice, rather than routine statutory controls
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disease surveillance and investigation remain robust and responsive to risk
We will continue to keep this approach under review as evidence and experience develop.
Who to contact if you suspect KHV
If you suspect or know of a listed disease of fish or shellfish in England and Wales (including KHV), you must report it immediately by contacting the Fish Health Inspectorate (FHI) at the Centre for Environment, Fisheries and Aquaculture Science (Cefas) by calling:
Telephone: 01305 206700
For urgent enquiries, including reporting disease suspicion, a 24/7 on-call service is available via this number.
- or emailing: fhi@cefas.gov.uk
You must also tell the FHI or a veterinarian immediately if you know or suspect that increased mortality has occurred.
If you do not report it, you are breaking the law.