Stone fish Synanceia Verrucosa

Stonefish hiding amoung the coral.

Photo: See the stonefish? It's hiding at the bottom

The stonefish is the world's most venomous fish. Its sting is extremely painful and can lead to heart failure and death. The stonefish is a bottom-dwelling fish that gets its name from its ability to disguise itself and blend into its environment. Its favourite disguise is to look like a coral-covered stone, hence its name—stonefish.

How Dangerous is the Stonefish? How Terrible is the Stonefish

stronefish hiding

Photo: Stonefish disguised as a stone

The stone fish is variously called the most dangerous, the most venomous fish, and even the most poisonous fish in the world. But is the stonefish really that terrible, and are these names for it fair?

The terms dangerous and deadly are usually used to refer to how harmful an animal is to humans. A stonefish's sting is indeed hazardous to humans. But a stonefish never attacks a human! Most encounters between stonefish and humans are accidental. The spines on the back of a stonefish are strictly for its own protection and are intended to keep the fish safe from predators. So, the stonefish is dangerous or deadly only if a human intentionally comes into contact with it, usually by accidentally stepping on it. So is a stonefish dangerous and deadly for humans? The answer is YES.

Photo: Stonefish dorsal fin spines

A venomous animal injects its toxin into another animal. Because the stonefish injects its highly toxic venom into its victim when its spins are compressed, it is the world's most venomous fish. So, is the stonefish venomous? The answer is YES.

By definition, a poisonous animal's entire body or parts of its flesh contain toxic substances that are harmful if touched or eaten. Sharks and rays eat stonefish and suffer no noticeable adverse effects. Humans, too, can eat the stonefish if they remove the venom glands feeding the spines or boil the animal to destroy its toxicity. Human deaths from eating stonefish are rare to non-existent. So, is the stonefish poisonous? Technically, the answer is NO.

So, in conclusion, the stonefish is the deadliest and most dangerous venomous fish in the world to humans.

• The Stonefish's Sting - Painful & Deadly

Stonefish Description What Does a Stonefish Look Like?

Photo: Stonefish blending into its environment

The stonefish is a stout, 35–50cm long fish with a large upward-opening mouth. The stonefish does not have scales. Its warty grey-brown skin is covered with bumps and nodules and has filaments and growths that appear like outgrowths of algae. The stonefish is a master of disguise. It has the uncanny ability to morph into various rock-like shapes and add splashes of colour to its appearance to mimic and blend in with its surroundings. Even its eyes can impersonate algae. The stonefish’s favourite camouflage is to look like an algae-covered rock. It also lies on soft sand or mud and, using its large pectoral fins as spades, it partially buries itself to appear like a rock on the sea-floor. Then, hidden by its excellent disguise, it waits motionless for prey to pass by.

The male and female stonefish are similar in appearance. However, the female is bigger and broader around the abdomen than the male and can weigh 50% more.

From a human perspective, it is the stonefish’s dorsal fin (the top fin on its back) that is the most dangerous. Thirteen fully covered spines support the dorsal fin. But unlike most fish, these hidden spines are hollow and connected to venom glands that discharge their contents along ducts in each spine. Usually, these sharp hypodermic needle-like spines are hidden beneath the skin of its dorsal fin. However, if the animal’s spine or dorsal fin is squeezed, these needle-like spines break through its skin and impale the attacker, injecting venom into the wound. These deadly spines are strictly defensive. It never uses them to capture or attack other animals.

The stonefish can survive out of water for up to 24 hours. This may be an adaptation to its shallow water existence, where it may get trapped in drying out rock-pools during low tide. It has a lifespan of between 5 to 10 years.

Worldwide there are five species of stonefish. Two species of stonefish are found in waters around Australia and are the most venomous. The only way to tell them apart is in the position of their eyes. The Reef Stonefish ( Synanceia verrucosa) has a deep depression between its eyes. The Estuary Stonefish ( Synanceia horrida) has elevated eyes separated by a bony ridge.

Stonefish Habitat Where Do Stonefish Live?

Photo: Stonefish Australian Location Map

The stonefish lives in shallow tropical waters of the Pacific and Indian Oceans to the Red Sea. Stonefish in Australia are found off the coastline especially in the Great Barrier Reef.

The stonefish usually lurks amongst coral and rock formations and camouflages itself to look like a clump of coral or a piece of rock. Where there isn't sufficient environmental cover to disguise itself, the stonefish will use its powerful pectoral fins to dig itself into the seabed and pretends to be something most appropriate to its surroundings, typically an algae-covered rock.

Stonefish Diet What Do Stonefish Eat?

Stonefish Catching Prey Video

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The stonefish eats other fish and bottom-dwelling invertebrates. It is a sit-and-wait ambush predator that stays motionless and grabs its prey when they swim close by. (See video).

The stonefish's capture technique is called ‘gape and suck’. The stonefish can expand the volume of its throat, which has extra pleated skin to allow expansion, and mouth in a split second. When it opens its powerful jaws wide open and expands its throat, it creates a significant vacuum suction pressure between the inside of its mouth and the outside environment which sucks its unsuspecting prey into its gaping mouth where it is swallowed whole. This action is so quick that it's all over in less than 1/100th of a second.

Stonefish Reproduction Stonefish Life-cycle

The stonefish is a solitary animal. The only time it actively seeks out another is during mating season for spawning. The female stonefish release a layer of large fertilised eggs on the sea-floor and the male comes along, releasing sperm over them. Young stonefish hatch within three days. They are well developed and self-sufficient from birth.

Stonefish Predators & Threats What Kills Stonefish?

The main predators of adult stonefish are sharks, stingrays, and sea snakes. Young stonefish are easy prey for other fish. Very few survive to adulthood.

Can You Eat a Stonefish?

Yes, you can eat a stonefish – provided it is prepared properly. The protein-based venom quickly breaks down when cooked. It is also safe to eat raw, provided the fish's dorsal fin with its associated venom is removed first. It is a delicacy in Japan and China.

Stonefish Conservation Status Is the Stonefish Endangered?

The worldwide stonefish population is not known. It is found throughout its various habitats. There is no evidence to suggest that it is threatened in anyway. The stonefish is not endangered.

Stonefish Attack Do Stonefish Attack Humans?

Stonefish do not attack humans. Its venomous dorsal fin spines are only for defence. They do what they have always done and stay hidden and motionless in their habitat with their venomous dorsal fin spines erect as a defence. Stonefish sometimes wash up near the shoreline or on beaches where humans may step on them or pick them up. So strictly speaking any injury suffered by a human is self-inflicted – You ventured into its habitat, stepped on it or touched it. You didn't leave the animal alone and got stung.

Stonefish Sting Can a Stonefish Kill You?

Photo: Stonefish dorsal spine

Photo: Human foot after stonefish sting

The stonefish is the most venomous fish in the world. Hidden beneath its dorsal fin are 13 spines with deadly spikes that act like hypodermic needles and inject highly toxic venom into any creature that comes in contact with them. The venom in these spines is only released-when pressure is applied to the stonefish’s spine, which means the venom is most often emitted when the stonefish is being attacked by a predator or stepped on by a human. Stonefish venom has both cardiovascular and neuromuscular toxicity. The pain caused by the venom is described as being immediate and excruciatingly painful and may last many days. The severity of the outcome is depended on the number of punctures suffered from these spines. Symptoms include muscular paralysis, breathing difficulties and shock. If left untreated heart failure and death may occur.

The stonefish is ranked as the 20th most venomous animal in the world. There have been no recorded human deaths in Australia as a result of an encounter with a stonefish. It is believed that several fatalities may occur in other Indo-Pacific areas, usually due to the lack of medical treatment. Stonefish antivenom is the second-most frequently administered antivenom in Australia.

Stonefish Treatment for Sting What to Do if You are Stung by a Stonefish

The best precautions against a stonefish injury are being alert, wearing sturdy footwear, and not touching or picking up these animals.

If you do step on a stonefish or are foolish enough to pick one up and get stung, wash the wound with cold water (saltwater is fine). Then apply heat to the wound for 30-90 minutes. Soaking the wound in very hot water (but not so hot that it causes burns on the victim) is one easy option. Heat may help destroy stonefish venom and provide some pain relief to the victim. Vinegar, supplied on most Australian beaches for use against jellyfish stings, is also said to reduce pain. These remedies are offer temporary relief only. Medical treatment should always be sought urgently.

Stonefish vs Scorpionfish What’s the Difference Between Stonefish & Scorpionfish

Stonefish and Scorpionfish are often confused.

The stonefish is best at pretending to be a stone and is capable of less colour-matching compared to the scorpionfish. It is also the most venomous fish in the world. Only its dorsal fin is venomous.

The scorpionfish has more prominent eyes and can change its colour to better match its surroundings, including colourful corals. It has venomous spines on its back as well as on its fins. It isn't as venomous as the stonefish.

25 Stonefish Facts

  1. The stonefish is about 40-50cm in length with a warty grey-brown skin and patches of other colours.
  2. The stonefish is the most venomous fish in the world.
  3. It has 13 highly venomous spines hidden under its skin and break out when the fish is squeezed or pressed.
  4. Stonefish venom has cardiovascular and neuromuscular toxicity.
  5. Its sting is excruciatingly painful and can cause death.
  6. It doesn't attack human.
  7. Instead, humans disturb it and get stung.
  8. The stonefish lives in shallow water off the Australian coastline.
  9. It is a stout 50cm long fish with excellent camouflage skills.
  10. Its skin is covered with nodules, bumps and other odd growths that appear like outgrowths of algae.
  11. Its favourite disguise is to pretend to be an algae-encrusted stone or clump of coral.
  12. The stonefish has a lifespan of 5-10years and can survive out of water for up to 24 hours.
  13. Male and females are similar in appearance, But the female is 50% larger.
  14. The stonefish is a hide-and-wait predator and snaps up its prey when it passes close by.
  15. It eats other fish and bottom-dwelling invertebrates.
  16. It has a huge upward-opening mouth that can catch prey in 1/100th of a second.
  17. It sucks its prey into its huge mouth.
  18. The stonefish can survive out of water for up to 24 hours.
  19. Stonefish and Scorpionfish are often confused.
  20. The main predators of the stonefish are sharks, stingrays, and sea snakes.
  21. Stonefish antivenom is the second-most frequently used antivenom in Australia.
  22. No humans in Australia die from stonefish stings. There are many death in other countries.
  23. There are five species of stonefish worldwide.
  24. If prepared correctly, you can eat a stonefish.
  25. It is a delicacy in Japan and China.