Stonefish grow to 30cm, and are among the most venomous of all fish species.
True to their name, stonefish look like rocks. Their bumpy skin is brown or grey with orange, red or green patches and camouflages them perfectly among rocks or rubble. Stonefish live on coral or rocky reefs and in rock pools, but they can also be found sleeping in mud or sand. They usually lie motionless and are often partially buried in rubble or sand.
Why are they dangerous?
Stonefish have 13 spines along their back. At the base of each spine are venom glands. When stonefish are disturbed, for example by being stepped on, the spines erect and venom is released. The venom is only used as a defence mechanism; stonefish do not use their venom for hunting.
The venom causes immediate and very severe pain that may last for days. The venom can also lead to swelling, tissue damage, nausea, cardiac effects, and shock.
If you get stung, leave the water immediately and seek urgent medical attention by calling 000.
Remove any spines that may be left in the skin, and soak the affected area in hot water (as hot as can easily be tolerated) to relieve the pain. A hot shower is an alternative if the affected are cannot be immersed in hot water.
Depending on the severity, hospital treatment may be needed to manage the effects of the venom.
If first aid measures are insufficient to manage the effects of the venom, a stonefish antivenom may have to be administered.
No deaths have been recorded in Australia (Underhill, 1987).
Most stonefish stings occur when someone accidentally steps on a stonefish. While stonefish are a natural part of our marine environment, the following measures can reduce the risk of a painful stonefish encounter.
Always swim between the red and yellow flags in bathing reserves patrolled by qualified surf lifesavers and lifeguards. They are trained in first aid and have hot water available for immediate treatment of a stonefish sting.
Take particular care around shallow rocky reefs, rock pools with a sandy bottom, and in sand or mud close to rocky areas. Wear sturdy, thick-soled shoes when wading around those areas and shuffle your feet when walking.
Do not pick up rocks on reefs – they may actually be stonefish!
Underhill, D. 1987. Australia's Dangerous Creatures. Readers Digest. Pp. 368.