Epizootic haematopoietic necrosis

Epizootic haematopoietic necrosis virus (EHNV)

Epizootic haematopoietic necrosis is a deadly disease of finfish. It could impact some of our native freshwater fish populations.

About this disease

Epizootic haematopoietic necrosis is caused by epizootic haematopoietic necrosis virus (EHNV). This virus kills a number of freshwater fish species.

EHNV flares up in Australia, killing large numbers of redfin or European perch.

Why this is a problem for New Zealand

EHNV could kill several native freshwater fish species in New Zealand, as well as rainbow trout.

Once established, aquatic diseases are extremely difficult to eradicate.

How it could get here

The virus could come to New Zealand through:

  • infected live or dead finfish
  • contaminated equipment (such as nets and containers)
  • contaminated water.

MPI has strict measures in place to limit the chances of EHNV making it through the border.

Where you may find it

Infected fish are mostly likely to be found in freshwater fish farms or rivers, lakes, and streams.

How to identify it

Diagnosing fish diseases requires laboratory testing. Signs of fish diseases are difficult to tell apart.

If you find hundreds of small dead fish:

  • photograph them
  • take note of the location and any landmarks
  • call 0800 80 99 66 

Note: This information is a summary of this disease's potential impacts on New Zealand.

Last reviewed: