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    Poisonous/Venomous B.C. Fish

    Environmental Injuries / Exposures

    Last Reviewed on Dec 13, 2023
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    First 5 Minutes

    There are many poisonous/toxic/stinging fish in the waters of British Columbia:

    • Spiny Dogfish (Mud-shark), Squalus acanthias.
    • Purple Sea Urchin, Strongylocentrotus purpuratus.
    • Ratfish, Hydrolagus colliei.
    • Lion’s Mane Jelly, Cyanea capillata.
    • Rockfish, Sebastes sp.

    Most cause minor effects.

    The most likely complication is bacterial infection if puncture is present.

    The most serious possible complications include anaphylaxis and puncture of vital organs.


    Most cause minor effects.

    Diving and surfing, or commercial fishing.

    Generally mild effects, with little conclusive evidence for recommended treatments.

    The most likely complication is bacterial infection.

    • Rock Fish (Sebastes sp.), member of the Scorpionfish family.
      • Many rock fish species in B.C., almost all have venomous dorsal spines.
      • Symptoms include localized pain and swelling out of proportion to puncture size.
      • Spontaneously resolve within hours.

    • Spiny Dogfish (Mud-shark), (Squalus acanthias), member of the Squalidae family.
      • Spines anterior to both dorsal fins which may puncture and secrete a venom into a wound.
      • Causes localized pain, erythema and edema for up to 7 days.(2)

    • Purple Sea Urchin, (Strongylocentrotus purpuratus)
      • Covered in calcium carbonate spines which may leave fragments behind.
      • Equipped with venomous jaw-like structures (pedicellarines) which can sting if held in prolonged contact with a person (e.g., while diving).
      • Sting causes localized pain, erythema, edema and may cause myalgias, tenosynovitis.(3)
      • May trigger allergic reactions or anaphylaxis.

    • Lion’s Mane Jelly, (Cyanea capillata)
      • Jelly’s can have tentacles extending 30m behind the bell, nematocysts transfer toxin to skin.
      • The sting usually causes mild symptoms including red weals, swelling, and localized pain.(4)
      • May be mistaken for decompression sickness in divers.

    • Ratfish, (Hydrolagus colliei)
      • The dorsal fin has a large venomous spine.

    Images accessed from Wikimedia Commons Internet commons.wikimedia.org. Available from: https://commons.wikimedia.org/w/index.php

    Diagnostic Process

    • For penetrating injuries resulting from spines in which the spine is embedded, x-ray, ultrasound are indicated followed by CT if inconclusive.
    • Lab-work low-yield.
    • History: Previous exposures/allergic reactions.
    • Tetanus UTD
    • Physical Exam: -ABCs, signs of anaphylaxis or infection (if late presentation)
    • Assess the wound, looking specifically for signs of puncture, discoloration indicating foreign bodies.

    Recommended Treatment

    No definitive management other than what can be extrapolated from similar species.


    ** Note: hot-water immersion should NEVER be performed along with local or regional anesthesia due to increased risk of local anesthetic systemic toxicity

    • Vinegar (4-6% acetic acid) applied for 30s is indicated as a decontaminant.
    • Thorough wound care including cleaning, irrigation with saline.
    • X-ray or U/S to assess for foreign bodies.
    • Tetanus prophylaxis 0.5mg IM DTaP x 1.
    • Prophylactic antibiotics are indicated in cases of deep penetration or likely retained foreign body, specifically covering skin flora and vibrio. Suggested coverage includes both:
      • First generation cephalosporin for skin flora coverage.
      • Doxycycline 100mg PO BID x 3-5 days for vibrio coverage.
    • Specific:
      • Ratfish, Hydrolagus colliei
        • Given the documented risk for deep penetrating injury in similar species, a low threshold for imaging of injuries near sensitive structures would be reasonable.
      • Lion’s Mane Jelly, Cyanea capillata
        • Anaphylaxis has been described after a second Lion’s Mane Jelly sting, patients presenting with anaphylactic symptoms should be treated with epinephrine per the anaphylaxis guidelines https://emergencycarebc.ca/clinical_resource/anaphylaxis-diagnosis-treatment/.
        • There is some evidence to suggest that topical corticosteroids are beneficial, however the effect is less than that of hot water immersion.
        • Domestic vinegar (4-6% acetic acid) may be applied to stings for 30s to prevent further nematocyst discharge.
        • Ice packs may be effective pain killers.

    Criteria For Hospital Admission

    Severe systemic involvement or IV antibiotics needed.

    Criteria For Transfer To Another Facility

    Dependent on resources available.

    Criteria For Close Observation And/or Consult

    • Severe systemic or anaphylactic symptoms.
    • Development of infectious s/s.

    Criteria For Safe Discharge Home

    • No signs of anaphylaxis or systemic symptoms.
    • Symptoms resolving.

    Quality Of Evidence?


    While there is little to no evidence specifically relating to the species described many marine envenomations do follow generic treatment algorithms with the exception of particularly potent creatures, none of which are present in B.C.


    Related Information


    Reference List

    1. Atkinson PRT. Is hot water immersion an effective treatment for marine envenomation? Emergency Medicine Journal. 2006 Jul 1;23(7):503–8.

    2. Evans HM. THE POISON OF THE SPINY DOG-FISH: A Case of Acute Oedema the Result of a Prick by a Dog-fish, and a Preliminary Note on the Poison Gland of the Spiny Dog-fish. BMJ. 1920 Feb 28;1(3087):287–8.

    3. Gelman Y, Kong EL, Murphy-Lavoie HM. Sea Urchin Toxicity [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2021 [cited 2021 May 2]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK536934/

    4. Trevett A, Sheehan C, Wilkinson A, Moss I. Lion’s mane jellyfish (Cyanea capillata) envenoming presenting as suspected decompression sickness. Diving and Hyperbaric Medicine Journal. 2019 Mar 31;49(1):57–60.

    5. Hayes AJ, Sim AJW. Ratfish (Chimaera) spine injuries in fishermen. Scottish Medical Journal. 2011 Aug;56(3):161–3.


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