Lionfish, Heron Island, Great Barrier Reef

This ornate-looking fish, while incredible to look at, is armed with up to 18 venomous fin spines that can inflict painful puncture wounds to the unsuspecting victim. Fatalities, however, are rare. Easily identified by its elongated fins, each species of lionfish has a pattern of zebra-like stripes. Read on to find out where you’ll find this fish lurking and what to do if stung.

What does a lionfish look like?

Usually growing to between 30 – 40cm in length, the fish have distinctive long pectoral and dorsal fins and the body is covered with red, brown, or black bands against a pale background. There may be white spots along the lateral line and a tentacle is usually present above both eyes. The tentacle varies in size and shape.

Where does it live?

It is a tropical species found widely throughout the Indo-Pacific. In Australia, it is found from south-western Western Australia, around the tropical north of the country and south to the southern coast of New South Wales. They can usually be found in coral reefs, especially in shallow waters hovering in caves or near crevices. 

Are they aggressive?

No, lionfish are not aggressive toward humans and will almost always keep their distance when given the opportunity, so they pose a relatively low risk.

How does a lionfish sting?

If a lionfish feels threatened it will point its fin spines towards its intruder. They are mainly used by the fish as a deterrent for predators though and aren’t used for hunting prey. They won’t, for example, ambush unsuspecting divers, so if you steer clear of their venomous spines, you should be fine.

If you are stung, a loose sheath surrounding each fin spine is pushed down. This compresses two venom glands located down the length of the spine and a neurotoxic substance then travels up the spine into the wound.

What are the symptoms of a sting?

Lionfish stings are rarely fatal, but in extreme cases, nausea, vomiting, and allergic reactions can occur. Swelling of the wounded area may also occur.

What should I do if stung?

  • Immerse the affected area (most often a hand or foot) into hot water. The water should be as hot as the patient can handle, but not so hot it burns. This is thought to deactivate the venom while also helping to ease the pain.
  • Continue to immerse the stung area for 30 minutes, replacing the water as it cools. Try to remove any remaining spine from the wound.
  • Be sure to seek a professional medical assessment of the wound as soon as possible, as a tetanus shot may need to be administered, and antibiotics may need to be prescribed.
  • An x-ray of the wound should be performed to detect any presence of broken spines that haven’t already been removed.   

How long will it take to recover from a sting?

Swelling typically clears in two-to-three days, while the tissue discolourations can last up to five days. Keep an eye on the wound for signs of infection, applying topical cream and taking antibiotics as prescribed by your doctor. 

Great Barrier Reef Blog