Listed diseases of fish, molluscs and crustacea and their status
Source: gov.uk (2025-08-21)

Guidance on listed  diseases of fish and shellfish and their status in England and Wales, including what happens if a disease is suspected or confirmed.

If you suspect a listed fish or shellfish disease

‘Listed’ diseases of fish and shellfish are diseases that you’re legally obliged to report immediately to the Fish Health Inspectorate (FHI), Cefas, even if you only suspect that an animal may be affected. They are also referred to as ‘notifiable’ diseases.

Listed diseases can be:
- endemic – already present in GB, such as Koi herpesvirus (KHV)
- exotic – not normally present in GB, such as Viral haemorrhagic septicaemia (VHS)
The listed diseases of fish and shellfish are in Commission Regulation (EC) 1251/2008 as amended by the Animals, Aquatic Animal Health, Invasive Alien Species, Plant Propagating Material and Seeds (Amendment) (EU Exit) Regulations 2020, at Chapter 2 (https://www.legislation.gov.uk/uksi/2020/1388/regulation/5/made) and Annex 1A , and Schedule 1 of The Aquatic Animal Health (England and Wales) Regulations 2009 (https://www.legislation.gov.uk/uksi/2009/463/contents).

If you suspect or know of a listed disease of fish and shellfish in England and Wales you must report it immediately to the FHI (https://www.gov.uk/guidance/report-serious-fish-or-shellfish-diseases#contact). You must also tell the FHI immediately if you know or suspect that increased mortality has occurred. Failure to do so is an offence and you could be fined up to £5,000.

Disease status for England and Wales

Fish

Crustaceans

Molluscs

Disease investigation and control

If the FHI suspects a listed or emerging disease:

an Initial Designation Notice is made to prevent further spread of disease from the affected area by restricting movements of fish or shellfish, and through application of additional biosecurity measures when required. An initial designation notice is not made public.

the FHI will carry out a disease investigation which includes collection of samples to test for the disease. Depending on the tests required it can take 14 days or more from receipt of sample at the laboratory to getting results. The FHI will advise the site operator on what to expect and keep them informed of progress.

if the tests are negative and listed or emerging disease is ruled out the Initial Designation Notice is lifted.

If a listed disease is confirmed:

a Confirmed Designation Notice (a legal order restricting movements of aquatic animals into, out of and within the affected area) is made to prevent or limit the spread of the disease from the affected area. A Confirmed Designation Notice is published on GOV.UK and signs may be put up in the affected area to inform the public.

further controls may include restricting vehicle and equipment movements, restricting site activities (like disposal of waste) or any other activity that could spread the disease, and additional biosecurity measures (like use of on-site equipment disinfection) may also be required.

the FHI investigate where the disease came from and whether it has spread, and put controls on sites where the disease could have spread from or to (for example when fish or shellfish have been moved or there are water and equipment connections) to prevent or limit further spread. These sites are also investigated on suspicion of listed disease.

a Confirmed Designation Notice can only be lifted when the FHI are satisfied that the disease is no longer present in the affected area. This may require the following actions: :

FHI supervise the stock cull, site clearance and disinfection.

and/or completion of a satisfactory monitoring and retest programme by FHI - this can be up to 4 years, any re-occurrence of the disease during that period means the programme must be restarted.

Controlling serious disease outbreaks

The Contingency Plan for Exotic Notifiable and Emerging Diseases of Aquatic Animals in England and Wales (https://www.gov.uk/government/publications/contingency-plan-for-exotic-notifiable-and-emerging-diseases-of-aquatic-animals-in-england-and-wales) outlines how government and its operational partners prepare for and respond to serious outbreaks of listed and emerging diseases.

How to prevent the introduction and spread of listed diseases

Prevention is the best approach to disease control. You can protect fish and shellfish from serious diseases by being vigilant about stock health and husbandry, quick to report any stock health concerns to the FHI, and by:

following strict biosecurity practices (https://www.gov.uk/guidance/biosecurity-measure-plans-information-and-templates). All authorised aquaculture production business must follow an approved biosecurity measures plan.

following the regulatory requirements (https://www.gov.uk/government/collections/aquatic-animal-health-and-movements-guides)

knowing the health status of the animals you are buying or moving

report suspicion of listed disease in fish and shellfish to the Fish Health Inspectorate (https://www.gov.uk/guidance/report-serious-fish-or-shellfish-diseases#contact) as soon as possible

Outbreaks of fish and shellfish disease

For up to date confirmed disease outbreaks (https://www.gov.uk/guidance/prevent-fish-or-shellfish-diseases#control-areas-for-notifiable-disease-outbreaks) in England and Wales.

Read the regulations

Listed fish and shellfish diseases are controlled by law under the Aquatic Animal Health (England and Wales) Regulations 2009 (http://www.legislation.gov.uk/uksi/2009/463/contents/made).

Contact

Email: xxx@xxx.xx (mailto:xxx@xxx.xx)

Telephone: xx-xxxx-xxxx

Monday to Thursday - 9:00 am to 5:00 pm, Friday 9:00 am to 4:30 pm

For emergencies out of hours telephone: xx-xxxx-xxxx

Fish Health InspectorateBarrack RoadThe NotheWeymouthDorsetDT4 8UB