About VHS

Viral hemorrhagic septicemia (VHS) is an infectious fish disease. It was first detected in Lake Ontario in 2005.

Outbreaks are most common in the spring when:

  • temperatures are fluctuating
  • fish are spawning

Affected fish species

Fresh and saltwater fish can catch VHS. The Great Lakes strain of the virus affects both game fish and baitfish species.

Game fish

  • walleye
  • yellow perch
  • muskellunge
  • smallmouth bass
  • rock bass
  • chinook salmon
  • black crappie
  • white bass


  • emerald shiners
  • bluntnose minnows
  • spottail shiners

Other species

  • freshwater drum
  • round goby
  • gizzard shad

How to identify VHS

Infected fish may show the following signs:

  • pale gills and organs
  • bloated abdomen
  • bulging eyes
  • hemorrhages (bleeding) on body and organs
  • darker body colour

Some fish show no signs of infection.

People and VHS

VHS is not a risk to human health:

  • the virus does not affect humans
  • fish carrying VHS are safe to eat and handle

However, it is never wise for people or pets to consume or handle fish that:

  • look sick
  • are dying
  • are already dead

How VHS spreads

VHS spreads in water, and by contact with infected fish and their body fluids. The virus can travel from one waterbody to another on anything it has contacted, including:

  • fish
  • water
  • boats
  • equipment

Ontario lakes where VHS is found

These lakes and parts of their tributaries are considered positive for VHS for all fish species:

  • Lake Ontario
  • Lake Erie
  • Lake Huron
  • Lake Simcoe (since 2011)

VHS management zones

The Ministry of Northern Development, Mines, Natural Resources and Forestry created two management zones to slow the spread of VHS:

  • VHS Management Zone in 2007
  • Lake Simcoe Management Zone in 2012

Map of Lake Simcoe management zone and VHS management zone

Map of the Lake Simcoe management zone

Management strategies

The Ministry of Northern Development, Mines, Natural Resources and Forestry (NDMNRF) is taking action to slow the spread of VHS. Management strategies include:

  • education and awareness efforts for anglers
  • restrictions on the movement of commercial baitfish
  • restrictions on the collection of and treatment of wild spawn for stocking
  • random sampling across Ontario
  • sampling from high-risk lakes and from reported die-offs

How anglers can help

Safe disposal

  • dump the contents of your bait container at least 30 metres from any lake, pond, river or stream
  • when cleaning fish, dispose of fish waste, heads and tails in the garbage, not waterways
  • put unwanted roe or baitfish in the garbage
  • empty livewells and bilges away from water, where the water will be absorbed into the ground

Don’t move fish

  • use locally harvested baitfish and roe
  • ask bait dealers where they got their supply to ensure they’re buying locally


  • remove mud, aquatic plants and animals from gear, boat motors and trailers before you go home


  • after fishing in a waterbody known to contain VHS:
    • clean and disinfect livewells with a 10% household bleach/water solution (e.g., 100 ml of household bleach to 900 ml of water)
    • empty all water 30 metres from any waterbody

How commercial bait operators can help

Safe disposal

  • don’t release live bait
  • empty bait containers at least 30 metres from any waterbody


  • remind customers it’s illegal to dump their bait
  • encourage them to use locally harvested bait

Separate and isolate

  • separate new and old shipments/catches of fish
  • avoid storing live baitfish in holding facilities directly connected through an inflow or outflow to natural waters


  • look for signs of disease when inspecting your catch or bait from other operators
  • report any suspected cases to your local NDMNRF office


  • clean and disinfect equipment and clothing before moving to a new waterbody:
    • disinfect with Virkon® S or a 10% household bleach/water solution
    • wash and rinse equipment 30 metres from waterbodies, dry thoroughly
    • use different gear and equipment for inside and outside the VHS management zones and label equipment accordingly

How aquaculturists can help


  • develop and implement a fish health management plan, including routine screening
  • contact your veterinarian if you suspect VHS or any illness
  • disinfect eggs collected from wild stock with an iodine-based solution during the water-hardening stage of fertilization
  • request a health certificate for the fish and eggs you import stating they are VHS-free

Separate and isolate

  • isolate sick fish to minimize the spread of disease
  • control facility effluent to minimize impact on natural waterbodies


  • Disinfect equipment regularly
    • use Virkon® S or a 10% household bleach/water solution
    • discard rinse water 30 metres from any waterbody
    • install disinfection stations at entries and exits

Safe disposal

  • collect dead fish in secure containers and dispose in landfill or compost
  • prevent predators and scavengers from gaining access to fish

Best practices for egg disinfection and incubation procedures for salmonids (salmon, trout and whitefish)

Best practices for egg disinfection and incubation procedures for muskellunge and walleye

How pond owners can help

To date, VHS hasn’t been found in any aquarium fish.

Don’t move live fish

  • don’t release fish into Ontario waters
  • don’t collect wild fish from any natural waterbody to stock an aquarium or water garden

Safe disposal

  • don’t flush dead fish down the toilet
  • bury or compost dead fish, or put them in the garbage
  • don’t pour water from your pond or aquarium into sewers or natural waterbodies

VHS bait

Can I bait my hook with eggs from the fish I catch?

  • You may strip fish roe (eggs) from your catch as long as:
    • you catch the fish legally
    • you do not discard or waste the fish after taking the roe
  • You may:
    • use fish roe anywhere organic bait is permitted 
    • share fish roe with other anglers
    • Not sell, trade or barter fish roe

For a complete list of fishing regulations, consult the Ontario Fishing Regulations Summary

Can I dump my bait bucket into the lake?

  • It’s illegal to empty your bait bucket, drain the water or release live baitfish into a lake, river or other waters.
  • Instead, you must:
    • drain your bucket onshore (30 metres from the water)
    • freeze the excess minnows for another day
    • catch your own bait from the lake you fish in

Learn more: fishing with live bait

For more information

For general inquiries, call the Natural Resources Information and Support Centre: 1-800-667-1940

To report fish die-offs, call: 1-866-929-0994

What to do about a fish die-off