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Fish Roundworm

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Commonly infected wildlife



Is this animal infected?

  • Infected fish have worms that are:
    • Often free in the fish's body cavity
    • 1/16"-1/8" long, less than 1/2" wide
    • White in color
    • Often in a coil shape

Fish Roundworm

Can I get it?


  • By consuming raw or undercooked fish

Caution: some people may develop allergic reactions after eating these worms

How bad can it get?

Beware: May require medical attention.

Protect myself and others

  • Gut and process fish immediately to stop worms from moving into the muscle
  • Kill worms in the muscle:
    • Cook fish to 165°F for 10 minutesor
    • Freeze at -15°F for seven days, especially when the fish will be prepared for sushi

165 °F

0 °F


Symptoms in humans

  • Occur within hours of eating infected fish
    • Severe stomach pain
    • Nausea and vomiting
  • Worms may enter the intestine 1-2 weeks after infection
    • Surgical removal may be necessary if worms burrow into the intestinal wall
    • Worms are occasionally coughed up
  • Seek medical advice if you become ill after eating raw or undercooked fish

Safe for pets?

Safe for pets

Yes, if the fish is well cooked (worms cannot survive in pets for long)


What causes it?

  • A roundworm called Anisakis simplex
  • Commonly known as herring worm