Cone Snail Conotoxin Harpoon Sting, Sea Snake Myotoxicity, and Crown-of-Thorns Starfish Plastertoxin Extraction¶

Across the coral reefs, lagoons, and coastal waters of the Indo-Pacific, Red Sea, Australia, and tropical Eastern Pacific, divers, snorkelers, shell collectors, and fishermen face three distinct marine envenomations with completely opposite mechanisms of injury and pre-hospital bandaging rules: piscivorous Cone Snails (Conus geographus, Conus tulipa, and Conus textile), venomous Sea Snakes and Sea Kraits (Subfamily Hydrophiinae and Laticauda), and the Crown-of-Thorns Starfish (Acanthaster planci). When a collector picks up a live geography cone snail (Conus geographus), the snail extends its tubular proboscis and fires a microscopic, hollow chitinous radular harpoon tooth (capable of piercing wet suits and gloves) that injects a synchronized cocktail of alpha-, mu-, and omega-conotoxins. This neurotoxic "cabal" blocks nicotinic acetylcholine receptors, skeletal muscle sodium channels, and presynaptic calcium channels simultaneously, triggering rapid, descending flaccid paralysis and diaphragmatic respiratory arrest within 15 to 60 minutes without any antivenom in existence. Conversely, a bite from a true Sea Snake (Hydrophis / Enhydrina / Aipysurus) is typically completely painless and nearly invisible (two tiny pinpricks with zero swelling), yet over 30 minutes to 6 hours its phospholipase A2 myotoxins dissolve skeletal muscle across the body (generalized myolysis / rhabdomyolysis), causing jaw stiffness, painful muscle movement, coal-black myoglobinuric urine, fatal hyperkalemic cardiac arrest, and neurotoxic respiratory paralysis requiring CSL Sea Snake Antivenom. Both Cone Snail stings and Sea Snake bites REQUIRE an immediate Australian Pressure Immobilization Bandage (PIB) plus splint. By contrast, stepping on or brushing against a Crown-of-Thorns Starfish (Acanthaster planci) drives dozens of brittle 5-centimeter calcium carbonate spines coated in plastertoxins (steroidal saponins) into the skin, causing immediate fiery pain, vomiting, and synovitis; it must NEVER be wrapped in a PIB, and instead requires 45 C (113 F) hot-water immersion and surgical/ultrasound spine extraction. If someone is stung or bitten by any of these marine organisms, call your local emergency numbers immediately. Also review our sibling guides on stingray barbs, sea urchin spines, and stonefish venom, jellyfish stings, and acute kidney injury and rhabdomyolysis.

Your immediate priority is to get the victim out of the water onto a boat or beach immediately before paralysis causes drowning, apply a broad elastic Pressure Immobilization Bandage (PIB) and rigid splint for any Cone Snail sting or Sea Snake bite, stand ready to perform mouth-to-mouth or bag-valve-mask rescue breathing if the diaphragm paralyzes, and for a Crown-of-Thorns Starfish spine injury, soak the limb in hot water at 42 to 45 degrees Celsius (108 to 113 degrees Fahrenheit) for 30 to 90 minutes without applying a pressure bandage.

Do this now¶

1. Pull the victim out of the water onto a boat deck, dock, or dry beach immediately, and call your local emergency number or Coast Guard marine rescue. Dial 000 in Australia, 111 in New Zealand, 911 in the United States, Canada, and the Philippines, 118 in Japan, 1669 in Thailand, 112 across the European Union, or check our global directory of emergency numbers. Both cone snail conotoxins and sea snake neurotoxins cause progressive flaccid respiratory paralysis while the victim is still fully conscious.
2. FOR A CONE SNAIL STING OR SEA SNAKE BITE: Apply a Pressure Immobilization Bandage (PIB) and rigid splint within 60 seconds, and keep the victim completely motionless.
3. Do NOT wash a sea snake bite site in Australia (hospital laboratories can swab the skin for a Venom Detection Kit if needed).
4. Wrap a 10- to 15-centimeter wide elastic bandage firmly over the sting or bite site, then wrap down to the fingers or toes and all the way up to the armpit or groin at 40 to 70 mmHg (the tightness used for a sprained ankle). Bind a rigid splint to the limb and carry the patient flat on a stretcher.
5. Watch the victim's eyelids, speech, swallowing, and breathing every 2 minutes; if breathing becomes shallow or stops, start immediate rescue breathing (mouth-to-mouth, pocket mask, or bag-valve-mask). Because there is NO antivenom for a Cone Snail sting, artificial ventilation (rescue breaths on the beach/boat, followed by hospital mechanical ventilation for 12 to 48 hours) is the 100% life-saving cure until the body clears the reversible conotoxins.
6. Never ignore a painless pinprick after handling a fishing net or wading in tropical Indo-Pacific waters. Over 80 percent of Sea Snake (Hydrophiinae) bites are completely painless and show no local swelling, leading fishermen and divers to ignore the bite until 1 to 4 hours later when trismus (locked jaw), drooping eyelids (ptosis), generalized muscle pain, and dark brown/black urine (myoglobinuria) appear.
7. FOR A CROWN-OF-THORNS STARFISH (Acanthaster planci) SPINE INJURY: NEVER apply a Pressure Immobilization Bandage. Instead, gently pull out any large protruding loose spines with forceps without crushing them, and immerse the stung hand or foot in hot water at 42 to 45 degrees Celsius (108 to 113 degrees Fahrenheit) for 30 to 90 minutes to inactivate heat-labile plastertoxins and saponins.
8. At the hospital: for a Sea Snake bite, infuse CSL Sea Snake Antivenom (or equine Tiger Snake / Polyvalent cross-reacting antivenom) and treat life-threatening hyperkalemia (IV calcium gluconate, insulin + dextrose); for a Crown-of-Thorns injury, obtain soft-tissue X-rays or ultrasound to surgically extract brittle subdermal spine tips.

Decision tree: Indo-Pacific marine envenomation triage and first aid¶

flowchart TD
    A["Indo-Pacific Coral Reef or Marine Envenomation"] --> B{"Which marine organism caused the injury?"}
    B -->|Picked up patterned cone shell; sharp harpoon sting followed by numbness, double vision, and spreading weakness| C["Cone Snail (Conus geographus / C. textile) Conotoxin Envenomation"]
    B -->|Paddle-tailed marine snake in net or reef; painless tiny pinpricks; delayed muscle ache, droopy eyelids, or dark urine| D["Sea Snake (Hydrophiinae) or Sea Krait (Laticauda) Bite"]
    B -->|Large multi-armed spiny starfish on coral; multiple reddish brittle spines embedded in hand/foot + fiery pain & nausea| E["Crown-of-Thorns Starfish (Acanthaster planci) Spine Injury"]
    C --> F["Apply Elastic Pressure Immobilization Bandage (PIB) + Rigid Splint immediately; keep patient flat and motionless"]
    D --> F
    F --> G{"Any ptosis, slurred speech, difficulty swallowing, or shallow breathing?"}
    G -->|Yes: Descending Flaccid Paralysis| H["Start immediate Rescue Breathing (Pocket Mask / BVM) + Call Emergency Number / Coast Guard for Intubation"]
    G -->|No: Early stage| I["Urgent Hospital ICU transport with PIB kept in place until resuscitation team is ready"]
    H --> J{"Cone Snail vs Sea Snake Hospital Protocol"}
    I --> J
    J -->|Cone Snail| K["NO Antivenom exists: Mechanical Ventilation for 12 to 48 hr until conotoxins clear -> Full neurological recovery"]
    J -->|Sea Snake| L["Infuse CSL Sea Snake Antivenom + 12-lead ECG & IV Calcium/Insulin for Hyperkalemia + IV fluids for Myoglobinuria"]
    E --> M["NEVER apply PIB; immerse limb in Hot Water 42 to 45 C (108 to 113 F) for 30 to 90 min"]
    M --> N["Hospital Care: Local nerve block + X-ray/Ultrasound to extract brittle calcareous spines + Tetanus & Vibrio antibiotics"]

Head-to-head comparison: Cone Snails vs Sea Snakes vs Crown-of-Thorns Starfish¶

Because these three reef inhabitants share the same Indo-Pacific habitat yet demand radically different hospital treatments, clinical comparison is critical:

Cone Snails (Conus geographus, C. tulipa, C. textile): Harpoon Mechanics and Conotoxin Paralysis¶

1. Why fish-hunting cone snails are lethal to humans¶

All 800+ species of marine cone snails (Genus Conus) are predatory carnivores that hunt marine worms (vermivorous), other mollusks (molluscivorous, such as the Cloth-of-Gold Cone, Conus textile), or agile reef fishes (piscivorous, led by the Geography Cone, Conus geographus, the Tulip Cone, Conus tulipa, and the Striated Cone, Conus striatus). - Evolutionary reason Conus geographus kills humans: Because a fish can swim away with a single flick of its tail after being stung, fish-hunting cone snails evolved a venom powerful enough to paralyze a vertebrate's entire neuromuscular system in less than 2 seconds. Over 70 percent of all recorded human cone snail fatalities worldwide are caused by Conus geographus. - How the Radular Harpoon Strikes Through Gloves and Pockets: Inside its shell, the cone snail manufactures a quiver of microscopic, hollow, barbed chitinous teeth (radular teeth, 5 to 10 millimeters long) shaped like miniature whale harpoons connected to a muscular venom bulb. When a diver or beachcomber picks up the shell (or puts a shell inside a mesh collecting bag or pocket), the snail extends an elastic proboscis that reaches across the entire length of the shell and fires the venom-filled harpoon straight through human skin, neoprene gloves, or thin wetsuits.

================================================================================
   CONE SNAIL CONOTOXIN "MOTOR CABAL" AT THE HUMAN NEUROMUSCULAR JUNCTION
================================================================================

    [Presynaptic Motor Axon]
         |            |
         | [CaV2.2]   |<--- 1. OMEGA-CONOTOXINS (e.g. MVIIA / CVID)
         | Blocked    |        Block presynaptic N-type calcium channels so
         +------------+        acetylcholine (ACh) vesicles CANNOT release.
          (Synaptic Cleft)
         +------------+
         | [nAChR]    |<--- 2. ALPHA-CONOTOXINS (e.g. GI / MI)
         | Blocked    |        Competitively block postsynaptic nicotinic ACh
         |            |        receptors on the muscle motor endplate.
         | [NaV1.4]   |<--- 3. MU-CONOTOXINS (e.g. GIIIA)
         | Plugged    |        Physically plug skeletal muscle sodium channels
    [Skeletal Muscle / Diaphragm]  so no muscle action potential can fire.

  --> RESULT: Total Neuromuscular Blockade -> Flaccid Diaphragmatic Arrest
  --> CURE: Immediate PIB + Rescue Breathing / Mechanical Ventilation (12-48 hr)
================================================================================

2. The Pharmacology of the Conotoxin "Motor Cabal" and Clinical Progression¶

A single Conus geographus harpoon sting injects over 100 distinct disulfide-rich small peptides (conotoxins), which work together in two coordinated physiological phases described by biochemist Baldomero Olivera: 1. The "Lightning-Strike Cabal" (Immediate Nerve Stunning): Delta-conotoxins inhibit sodium channel inactivation while kappa-conotoxins block potassium channels on sensory and motor axons near the sting site, causing an immediate storm of nerve firing perceived as a sharp sting followed within minutes by spreading numbness. 2. The "Motor Cabal" (Total Triple-Lock Neuromuscular Blockade): Unlike a cobra or sea snake that attacks only one target at the neuromuscular junction, Conus geographus venom simultaneously shuts down all three steps of neuromuscular transmission: - Presynaptic Calcium Blockade (Omega-conotoxins): Blocks voltage-gated N-type calcium channels (CaV2.2) on the motor nerve terminal (the peptide from Conus magus that became the intrathecal chronic pain drug ziconotide), preventing acetylcholine exocytosis. - Postsynaptic Receptor Blockade (Alpha-conotoxins): Competitively blocks muscle-type nicotinic acetylcholine receptors (nAChR) at the motor endplate (like curare). - Muscle Membrane Sodium Blockade (Mu-conotoxins): Physically plugs voltage-gated skeletal muscle sodium channels (NaV1.4) so the muscle fiber cannot depolarize even if acetylcholine binds. - (Note: Conus geographus also secretes a specialized weaponized fish-like venom insulin [Con-Ins G1] that lowers blood glucose.) 3. Human Symptom Timeline (10 to 60 Minutes): - Minutes 1 to 15: Numbness and paresthesia spread rapidly from the stung finger up the arm, followed by perioral tingling around the lips and mouth. - Minutes 15 to 30 (Cranial Nerve Palsies): Blurred vision, diplopia (double vision), bilateral ptosis (drooping eyelids), dysarthria (slurred speech), and dysphagia (inability to swallow saliva), accompanied by absent gag reflex. - Minutes 30 to 60 (Diaphragmatic Arrest): Generalized flaccid skeletal muscle paralysis descends to the intercostal muscles and diaphragm, causing silent hypercapnic and hypoxic respiratory arrest within 30 minutes to 2 hours if unventilated. 4. Hospital ICU Management of Cone Snail Envenomation: - Keep the PIB in place until the patient is in the resuscitation bay with airway intubation gear ready. - Endotracheal Intubation and Mechanical Ventilation: Intubate immediately for decreasing respiratory effort, pooling oral secretions, hypoxia, or hypercapnia. - Trial of Anticholinesterase (Neostigmine): While mu- and omega-conotoxins act upstream and downstream of the acetylcholine receptor, clinicians may attempt a cautious trial of neostigmine (0.04 mg/kg IV) preceded by atropine (0.6 mg IV) to partially counter the competitive alpha-conotoxin block in mild cases, though mechanical ventilation remains the definitive life-saving therapy. With 12 to 48 hours of mechanical ventilation, conotoxins dissociate and the patient makes a 100% complete neurological recovery.

Sea Snakes (Hydrophiinae) and Sea Kraits (Laticauda): Painless Bite, Myolysis, and Hyperkalemia¶

1. Why Sea Snake bites are missed until Black Urine and Locked Jaw appear¶

True sea snakes (Subfamily Hydrophiinae, including the Beaked Sea Snake [Enhydrina schistosa / Hydrophis schistosus], Olive Sea Snake [Aipysurus laevis], Stoke's Sea Snake [Hydrophis stokesii], and Yellow-Bellied Sea Snake [Hydrophis platura]) and amphibious sea kraits (Genus Laticauda) possess some of the highest drop-for-drop venom lethality of any snakes on Earth. - Why Victims Ignore the Bite: Sea snakes have very short, fixed hollow front fangs (only 1.5 to 4 millimeters long) and their venom lacks the tissue-dissolving metalloproteases found in pit vipers. Consequently, a sea snake bite feels like a tiny, painless pinprick and leaves 1 to 4 pinpoint dots with zero swelling, zero redness, and zero pain at the bite site. - The Myotoxic + Neurotoxic Clinical Triad (Onset 30 Minutes to 6 Hours): While about 50 to 70 percent of defensive bites are "dry" (no venom injected), every sea snake bite that injects venom produces a systemic syndrome dominated by global skeletal muscle breakdown (rhabdomyolysis) alongside postsynaptic/presynaptic neurotoxicity: 1. Trismus (Locked Jaw) and Generalized Painful Myolysis: Within 30 to 120 minutes, the patient develops stiffness and aching pain in the neck, throat, and jaw (trismus: inability to open the mouth wide), followed rapidly by agonizing generalized pain across all large skeletal muscles (shoulders, back, thighs) whenever a clinician passively moves the patient's limbs ("pseudoparalysis" due to extreme muscle tenderness). 2. Coal-Black Myoglobinuric Urine (3 to 6 Hours): Venom phospholipase A2 (PLA2) myotoxins hydrolyze the phospholipid bilayers of skeletal muscle fibers throughout the body, dumping massive quantities of myoglobin, creatine kinase (CK often exceeding 50,000 to 200,000 U/L), aspartate aminotransferase (AST), potassium, and phosphate into the bloodstream. Within 3 to 6 hours, the patient's urine turns deep red-brown to pitch black (myoglobinuria), precipitating myoglobin casts in the renal tubules and causing oliguric acute kidney injury (AKI). 3. Lethal Hyperkalemic Cardiac Arrest and Flaccid Respiratory Paralysis: Massive potassium release from lysed muscle fibers causes rapid, life-threatening hyperkalemia (serum K+ rising above 6.5 to 8.5 mEq/L) within 4 to 12 hours (peaked T waves, widened QRS complexes, sine-wave pattern, and ventricular fibrillation or asystole), while alpha-neurotoxins cause bilateral ptosis, ophthalmoplegia, bulbar palsy, and respiratory failure.

2. Hospital Antivenom and Hyperkalemia Protocol for Sea Snake Envenomation¶

1. Immediate Pre-Hospital PIB + Splint: Apply a firm Australian Pressure Immobilization Bandage (PIB) and rigid splint immediately upon suspecting any sea snake bite, even if the bite is completely painless and the patient feels fine initially.
2. CSL Sea Snake Antivenom (The Definitive Antidote):
3. Administer CSL Sea Snake Antivenom (equine F(ab')2 raised against Enhydrina schistosa / Notechis scutatus, which cross-neutralizes all major Hydrophiinae sea snakes and Laticauda sea kraits) immediately to any patient showing early systemic signs (trismus, muscle pain/tenderness, ptosis, leukocytosis, rising CK, or dark urine).
4. Dosing: Start with 1 ampoule (1,000 units) diluted 1:10 in isotonic saline infused IV over 20 to 30 minutes (with bedside epinephrine ready for anaphylaxis). For severe envenomation (established paralysis, severe myoglobinuria, or hyperkalemia), infuse 3 to 10 ampoules IV promptly.
5. Emergency Backup Antivenom Rule: If dedicated CSL Sea Snake Antivenom is temporarily unavailable in a remote hospital, CSL Tiger Snake Antivenom works as an effective cross-neutralizing substitute.
6. Aggressive Hyperkalemia and Rhabdomyolysis Resuscitation:
7. Obtain an immediate 12-lead ECG and stat blood gas/electrolytes. If hyperkalemia (K+ > 6.0 mEq/L) or ECG changes (peaked T waves / wide QRS) are present:
   • Stabilize the myocardium immediately: Give 10% Calcium Gluconate (10 to 30 mL IV over 5 minutes) or 10% Calcium Chloride (5 to 10 mL IV via central line).
   • Shift potassium intracellularly: Infuse Regular Insulin (10 units IV) + 50 mL of 50% Dextrose (25 g glucose), plus high-dose nebulized Albuterol (Salbutamol 10 to 20 mg) and Sodium Bicarbonate (50 to 100 mEq IV) if acidotic.
   • Remove potassium and protect the kidneys: Infuse aggressive isotonic crystalloids to maintain urine output above 200 mL/hour, and initiate emergency hemodialysis for refractory hyperkalemia or oliguric renal failure.

Crown-of-Thorns Starfish (Acanthaster planci): Plastertoxin Spines, Hot Water, and Extraction¶

1. Spine anatomy and why retained tips cause chronic synovitis¶

The Crown-of-Thorns Starfish (Acanthaster planci) is a large, nocturnal corallivorous asteroid (growing 25 to 45 centimeters across with 8 to 21 arms) covered on its upper surface by hundreds of needle-sharp, 4- to 5-centimeter calcareous (magnesium-calcite) spines. - How the Venom Is Delivered: Each spine is enveloped in a thin, reddish-brown integumentary skin sheath containing glandular cells that secrete plastertoxins I and II (potent basic phospholipase A2 enzymes that are hemolytic, myotoxic, and mouse-lethal), asterosaponins (detergent-like steroidal glycosides that lyse cell membranes and trigger massive histamine and prostaglandin release), and histamine-like amines. - Why the Spines Break Off: Because the spine core is a porous, brittle lattice of calcium carbonate crystal (stereom), stepping on or brushing against an Acanthaster planci drives multiple spines through booties or bare skin, where the brittle tips snap off flush beneath the epidermis and shed strips of toxic integumentary skin inside the dermis or finger/foot joint capsules. - Clinical Syndrome: Instantaneous, excruciating burning pain radiating up the limb, brisk bleeding from multiple puncture holes, rapid local edema and ecchymosis, and in multi-spine injuries, systemic nausea, protracted vomiting, dizziness, paresthesias, and regional lymphadenitis. If subdermal calcareous spine tips and toxic epithelium are left inside the hand or foot, the patient develops foreign-body granulomas, secondary Vibrio / Mycobacterium marinum infection, and debilitating chronic granulomatous tenosynovitis or arthritis.

2. Step-by-step management of Crown-of-Thorns Starfish injuries¶

1. NEVER Apply a Pressure Immobilization Bandage (PIB): Wrapping a tight bandage over Acanthaster spines drives brittle calcareous shards deeper into tendons and joints and concentrates cytolytic saponins and phospholipase A2 locally.
2. Immediate Hot-Water Immersion (42 to 45 degrees Celsius [108 to 113 degrees Fahrenheit]):
3. Immerse the stung hand, foot, or limb in tolerably hot water (42 to 45 C / 108 to 113 F, tested first with an uninjured hand) for 30 to 90 minutes.
4. Plastertoxins and pain-mediating proteins are heat-labile; hot water immersion rapidly reduces pain from 9/10 down to manageable levels within 20 to 30 minutes.
5. Hospital Nerve Block, Radiographic/Ultrasound Localization, and Surgical Extraction:
6. Do not try to crush embedded spines with rocks or hammer them inside the skin (an harmful Indo-Pacific folk practice that shatters the porous calcite into hundreds of unremovable micro-granuloma fragments), and do not soak in vinegar hoping to dissolve deep subdermal spines overnight.
7. In the clinic or hospital, administer a local or regional nerve block (lidocaine or bupivacaine), obtain soft-tissue plain-film X-rays and/or high-frequency ultrasound (all calcium carbonate Acanthaster spines are radiopaque on X-ray), and use a surgical scalpel, operating loupes, and fine micro-forceps to extract every embedded spine tip and scrub out all dark pigmented integumentary sheath tissue.
8. Irrigate copiously with sterile normal saline, leave deep punctures open to drain, administer a tetanus booster, and prescribe doxycycline (100 mg PO twice daily) or ciprofloxacin (500 mg PO twice daily) plus amoxicillin-clavulanate for 5 to 7 days to cover marine Vibrio vulnificus, Vibrio alginolyticus, and Aeromonas species.

Regional emergency numbers and agency protocols¶

• Australia and New Zealand: Dial 000 in Australia or 111 in New Zealand, or hail Marine Rescue / Coast Guard on VHF Channel 16. Follow ANZCOR Guideline 9.4.5 (Envenomation: Jellyfish Stings and Marine Envenomation) and Guideline 9.4.1 (Snake Bite): apply an immediate Pressure Immobilization Bandage (PIB) + splint for Cone Snails and Sea Snakes, and apply Hot Water Immersion (42 to 45 C) without PIB for Crown-of-Thorns Starfish. Call the Australian Poisons Information Centre at 13 11 26 for CSL Sea Snake Antivenom logistics.
• Southeast Asia and Japan (Philippines, Indonesia, Thailand, Malaysia, Vietnam, Okinawa/Japan): Dial 911 in the Philippines, 112 / 119 in Indonesia, 1669 in Thailand, 999 in Malaysia, 115 in Vietnam, or 119 / 118 (Japan Coast Guard) in Japan. In Okinawa and Amami (Japan), where Conus geographus (Anboina), Laticauda sea kraits (Erabu-umihebi), and Acanthaster planci (Onihitode) are well-known hazards, prefectural hospitals stock marine antivenoms and provide immediate ICU mechanical ventilation.
• United States (Hawaii, Guam, American Samoa, California/Southwest Coast, and Captive Reef Aquariums): Dial 911 or contact the US Coast Guard on VHF Channel 16, US Poison Control at 1-800-222-1222, and the Divers Alert Network (DAN) Emergency Hotline at +1-919-684-9111. Note that the pelagic Yellow-Bellied Sea Snake (Hydrophis platura) occasionally washes ashore on Southern California, Baja California, and Hawaiian beaches after El Niño warming events; never touch a stranded sea snake on the beach.
• United Kingdom and European Union (Red Sea / Indo-Pacific Travellers & Reef Aquarists): Dial 999 in the UK, 112 across the EU, or 123 in Egypt (Red Sea diving resorts), and consult NPIS / TOXBASE for exotic aquarium cone snail or Acanthaster stings.

Frequently asked questions¶

Why is the Geography Cone Snail (Conus geographus) called the "cigarette snail," and how do you survive a sting?¶

In the Indo-Pacific, Conus geographus earned the nickname "cigarette snail" from the exaggeration that after a sting, you have only enough time to smoke one cigarette before respiratory arrest occurs. In clinical reality, its radular harpoon injects a synchronized cocktail of alpha-, mu-, and omega-conotoxins that block neuromuscular transmission at three separate sites, causing descending flaccid paralysis and stopping the diaphragm within 15 to 60 minutes. Although no antivenom exists, you can survive 100 percent of the time if rescuers immediately apply a Pressure Immobilization Bandage (PIB), perform continuous mouth-to-mouth or bag-valve-mask rescue breathing when breathing weakens, and place the patient on a hospital mechanical ventilator for 12 to 48 hours until the body naturally clears the conotoxins.

How can a deadly Sea Snake bite be completely painless at first?¶

Unlike rattlesnakes or cobras, sea snakes (Hydrophiinae) evolved venom specifically to immobilize fish and eels in the water and lack the tissue-dissolving enzymes that cause burning pain and swelling at the bite site. In addition, their fixed front fangs are only 1.5 to 4 millimeters long. A sea snake bite feels like a tiny, harmless pinprick with zero swelling or redness, so fishermen and waders often ignore it until 30 minutes to 4 hours later when their jaw locks stiffly (trismus), all their skeletal muscles become agonizingly painful to move, and their urine turns coal-black from widespread muscle breakdown (rhabdomyolysis).

Why does a Sea Snake bite turn your urine black and stop your heart?¶

Sea snake venom contains systemic phospholipase A2 myotoxins that circulate through the bloodstream and dissolve the outer membranes of skeletal muscle fibers across the body. As muscle cells burst open, they dump massive amounts of brown-black myoglobin protein into the blood, which filters through the kidneys and turns the urine dark reddish-brown or coal-black (myoglobinuria). Simultaneously, the bursting muscle cells dump massive amounts of intracellular potassium into the blood (hyperkalemia), which can trigger fatal cardiac arrest (ventricular fibrillation) within hours unless treated with CSL Sea Snake Antivenom, intravenous calcium gluconate, and insulin with glucose.

Should I use a Pressure Immobilization Bandage or hot water for a Crown-of-Thorns Starfish sting?¶

Use hot water immersion (42 to 45 degrees Celsius [108 to 113 degrees Fahrenheit] for 30 to 90 minutes), and NEVER apply a Pressure Immobilization Bandage (PIB) to a Crown-of-Thorns Starfish (Acanthaster planci) injury. Wrapping a tight bandage over a starfish wound pushes the brittle calcium carbonate spines deeper into your joints and tendons and traps saponins and plastertoxins in one spot. Soaking the foot or hand in hot water denatures the heat-sensitive plastertoxins and relieves the fiery pain until a doctor can take an X-ray and surgically remove the broken spine tips.

Why can't you just leave broken Crown-of-Thorns Starfish spines in your hand or foot to dissolve on their own?¶

Although Crown-of-Thorns Starfish spines are made of porous calcium carbonate, each spine is coated in a toxic outer skin sheath packed with plastertoxins and saponins, plus marine bacteria like Vibrio and Mycobacterium marinum. If broken spine tips and shreds of toxic skin remain embedded under your dermis or inside a finger or toe joint, the body forms painful foreign-body granulomas and chronic granulomatous synovitis that can stiffen the joint. Every embedded spine shard shows up on a soft-tissue X-ray or ultrasound and must be surgically removed under a nerve block.

Can a cone snail sting you through gloves or while inside a mesh collecting bag?¶

Yes. Never pick up a live cone shell with bare or gloved hands, and never put a live cone shell into a wetsuit pocket or mesh bag hanging against your leg or waist. A piscivorous cone snail like Conus geographus or Conus striatus can extend its flexible proboscis to the back end of its shell and fire its needle-sharp radular harpoon straight through cloth bags, dive gloves, and thin wetsuits.

Sources and official guidance¶

• Australian Resuscitation Council (ANZCOR, Australia and New Zealand): ANZCOR Guideline 9.4.5 (Marine Envenomation: Cone Shell PIB Protocol vs Echinoderm Spine Management) and ANZCOR Guideline 9.4.1 (Snake Bite / Sea Snake Protocol).
• Therapeutic Guidelines: Toxicology and Toxinology (eTG Complete, Australia) & AVRU: Clinical Management of Sea Snake (Hydrophiinae) Myotoxicity, Hyperkalemia, and CSL Sea Snake Antivenom; Cone Snail Paralysis; and Acanthaster planci Spine Debridement.
• Physiological Reviews: Calcium Channel, Sodium Channel, and Nicotinic Receptor Conotoxins of Piscivorous Conus Species (Terlau & Olivera, Physiological Reviews).
• World Health Organization (WHO): Guidelines for the Management of Snakebites: Sea Snakes (Hydrophiinae and Laticauda), Rhabdomyolysis, Myoglobinuria, and Hyperkalemia.
• Divers Alert Network (DAN) & Wilderness Medical Society (WMS): Hazardous Marine Life: Indo-Pacific Cone Snails, Sea Snakes, and Crown-of-Thorns Starfish.

Related guides¶

• Stingray barbs, sea urchin spines, and stonefish venom
• Acute kidney injury, rhabdomyolysis, and dark urine triage
• Snake bites and venomous reptile emergencies
• Botulism, ciguatera, scombroid, and marine neurotoxin poisoning
• Emergency numbers by country