New legislation has made it a legal requirement to report the suspicion that fish may be infected by the deadly Koi Herpes Virus.
A statutory control has been introduced under the Diseases of Fish (England and Wales) Order 2007 and makes it a legal obligation for any person, including fish farm or fishery owners or their staff, fishkeepers, fish dealers and fish suppliers to notify the Fish Health Inspectorate (FHI) if they suspect that fish may be infected with KHV.
Anyone required to notify the authorities who fails to do so without reasonable excuse would be guilty under the Diseases of Fish Act 1937 and could be prosecuted.
The Fish Health Inspectorate says that any fishkeepers who believe that their Koi are infected with the virus must also contact them.
The Fish Health Inspectorate will make a diagnosis on the basis of information provided about the clinical signs of disease and assess the potential for the spread of infection:
"Where the spread of infection is assessed as negligible, no further action will be taken by the FHI. Site owners will instead be provided with written advice on the management of KHV disease in aquaria and garden ponds.
"Where the assessment indicates potential spread to inland waters, a sample will be taken for diagnostic purposes and, on confirmation of the disease, a cull of the affected fish and disinfection of the facility will be advised.
"If this is not feasible a Designated Area Order will be placed on the site to prohibit the movement of fish on or off the site."
For fish suppliers, if the FHI suspects KHV, they may immediately prohibit movements of fish on and off the site by a thirty-day notice (TDN).
Cy HV-3Koi Herpes Virus, which is now formally known as Cyprinid Herpes Virus-3 (Cy HV-3) causes high levels of mortality in Common carp and Koi and usually only shows its symptoms when the water temperature is between 15 and 28°C.
Affected fish typically have sunken eyes, bleeding gills, white patches on the skin and gills and sometimes hyperactive behaviour.
The Ornamental Aquatic Trade Association (OATA), which has produced a document for retailers and fishkeepers to explain more about the disease, says that 80-100% of mortalities occur within 10 days, with most fish becoming sick and dying in just 24-48 hours.
Since the virus appears to suppress a fish's immune system, the body is unable to fight infection, so secondary bacterial infections and parasitic diseases are also apparent.