Bites, stings, and trauma from water hazards each need a different response — treating them all the same way can make things worse. Find the right one below.
This page is not a diagnosis
A photo of a marine animal or a sting mark can't confirm the species, how severe an exposure is, or whether the water nearby is safe. For a plausible serious exposure — a possible crocodile bite, tropical jellyfish sting, or blue-ringed octopus bite — call 000 now rather than looking for an identification first.
Crocodylus porosus
Largest living reptile. Extremely dangerous apex predator.
Where it may occur
Northern Australia. Habitat: Rivers, estuaries, coastal areas, sometimes open ocean.
Do not approach
NEVER enter water in croc territory. Keep 50m+ from water's edge. Obey all warning signs. Potentially fatal.
If exposure is possible: Crocodile Attack
What a photo cannot tell you
A photo can't confirm whether the water is currently safe, whether other crocodiles are nearby, or the extent of an injury.
Crocodylus johnstoni
Smaller than saltwater crocs. Less aggressive but can still bite if provoked.
Where it may occur
Northern Australia. Habitat: Freshwater rivers, billabongs, wetlands.
Do not approach
Do not swim in known croc waters. Keep distance. Can bite if cornered or protecting nest.
If exposure is possible: Crocodile Attack
What a photo cannot tell you
A photo can't confirm whether the water is currently safe, whether other crocodiles are nearby, or the extent of an injury.
Hapalochlaena species
A small marine animal with a potentially life-threatening bite. Never touch it, even if it looks still or small.
Where it may occur
Coastal Australia. Habitat: Rock pools, coral reefs, shallow water.
Do not approach
NEVER touch or handle. Venom is lethal. No antivenom. Seek immediate emergency care if bitten.
If exposure is possible: Blue-Ringed Octopus Bite
What a photo cannot tell you
A photo can't confirm whether a bite actually occurred — blue-ringed octopus bites are often painless — or how much venom was delivered.
Chironex fleckeri
Extremely venomous jellyfish. Can be fatal. Most dangerous during stinger season.
Where it may occur
Northern Australia. Habitat: Northern tropical waters, beaches, estuaries.
Do not approach
Swim in stinger nets only. Wear stinger suit. Vinegar for stings. IMMEDIATE medical emergency.
If exposure is possible: Box Jellyfish / Irukandji Sting
What a photo cannot tell you
A photo can't confirm the exact species, how much venom was delivered, or whether a delayed reaction like Irukandji syndrome will develop.
Carukia barnesi
Tiny tropical box jellyfish. A sting can cause delayed, severe Irukandji syndrome and needs urgent medical assessment.
Where it may occur
Northern Australia. Habitat: Tropical marine waters, reefs and offshore settings.
Do not approach
Stinger suits offer some protection. Seek IMMEDIATE emergency care if stung. Can be fatal.
If exposure is possible: Box Jellyfish / Irukandji Sting
What a photo cannot tell you
A photo can't confirm the exact species, how much venom was delivered, or whether a delayed reaction like Irukandji syndrome will develop.
Synanceia verrucosa
Extremely well camouflaged fish with venomous dorsal spines. A sting is one of the most painful marine injuries and usually needs hospital treatment.
Where it may occur
Great Barrier Reef, Queensland to far northern NSW. Habitat: Reef flats, rubble, sandy and muddy-bottom shallow water.
Do not approach
Never walk on reef flats or rubble barefoot — wear reef shoes. Do not touch anything that could be a camouflaged fish.
If exposure is possible: Stonefish Sting
What a photo cannot tell you
A photo can't confirm whether a spine broke the skin or how much venom was injected — stonefish are often invisible against the seabed until it's too late.
Physalia utriculus
Common beach stinger that washes ashore in groups after wind. Painful but rarely dangerous — treated very differently from tropical box jellyfish.
Where it may occur
All Australian coastlines, more common after onshore winds. Habitat: Ocean beaches, floats onto sand after wind.
Do not approach
Avoid entering water with bluebottles washed up on the sand or visible in the shallows. Do not touch a beached one — the tentacle can still sting.
If exposure is possible: Bluebottle Sting
What a photo cannot tell you
A photo can't confirm how much tentacle contact occurred or whether the reaction will stay mild or become more serious.
Guidance last reviewed: September 2026. Sources: Healthdirect Australia — Sea creature stings, Queensland Government — Dangerous marine life. This is general information, not a substitute for professional medical care. In an emergency, always call 000.