Poisonous/Venomous B.C. Fish
Environmental Injuries / Exposures
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.
Context
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.

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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.
GENERAL:
- Signs of shock should be treated according to https://emergencycarebc.ca/clinical_resource/undifferentiated-shock-diagnosis-and-treatment/.
- Pain Control (NSAIDs, acetaminophen, local anesthesia).
- Removal of foreign body material.
- Hot water immersion for 30-90 minutes with 42-45 degree °C water, or the hottest temperature tolerated, is indicated in the link above.
** 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.
- Ratfish, Hydrolagus colliei
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?
High
We are highly confident that the true effect lies close to that of the estimate of the effect. There is a wide range of studies included in the analyses with no major limitations, there is little variation between studies, and the summary estimate has a narrow confidence interval.
Moderate
We consider that the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. There are only a few studies and some have limitations but not major flaws, there are some variations between studies, or the confidence interval of the summary estimate is wide.
Low
When the true effect may be substantially different from the estimate of the effect. The studies have major flaws, there is important variations between studies, of the confidence interval of the summary estimate is very wide.
Justification
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
OTHER RELEVANT INFORMATION
Reference List
Atkinson PRT. Is hot water immersion an effective treatment for marine envenomation? Emergency Medicine Journal. 2006 Jul 1;23(7):503–8.
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.
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/
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.
Hayes AJ, Sim AJW. Ratfish (Chimaera) spine injuries in fishermen. Scottish Medical Journal. 2011 Aug;56(3):161–3.
RESOURCE AUTHOR(S)
DISCLAIMER
The purpose of this document is to provide health care professionals with key facts and recommendations for the diagnosis and treatment of patients in the emergency department. This summary was produced by Emergency Care BC (formerly the BC Emergency Medicine Network) and uses the best available knowledge at the time of publication. However, healthcare professionals should continue to use their own judgment and take into consideration context, resources and other relevant factors. Emergency Care BC is not liable for any damages, claims, liabilities, costs or obligations arising from the use of this document including loss or damages arising from any claims made by a third party. Emergency Care BC also assumes no responsibility or liability for changes made to this document without its consent.
Last Updated Dec 13, 2023
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