Stonefish Fish What is a Stone Fish?

Photo: Stonefish disguised as a stone

The stonefish is a highly venomous bottom-dwelling fish found in coastal regions of Australia and the Indo-Pacific. Its oval body is covered with bumps, nodules, filaments, and growths resembling algae. This camouflage enables it to blend in among rocks and sand by appearing like a stone, hence its name. The stonefish has 13 dorsal spines that deliver potent neurotoxins, causing excruciating pain, paralysis, and sometimes death to humans if stepped on or disturbed. Fortunately, there have been no recorded deaths from stonefish stings in Australia. Hidden by one of its excellent disguises, the stonefish waits motionless for prey to pass by and grabs them with its large upward-opening mouth.

Worldwide, there are five species of stonefish. The two species found in waters around Australia are the most vicious. 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. Male and female stonefish are similar in appearance. However, the female is larger and broader around the abdomen than the male and can weigh 50% more. Stonefish have a lifespan of between 5 to 10 years.

• 25 Stonefish Facts Summarised

Photo: Stonefish blending into its environment

How Dangerous is the Stonefish? How Deadly is the Stonefish

Photo: Stonefish dorsal fin spines

The stonefish is known as the most dangerous, venomous, and poisonous fish in the world. But is the stonefish really that dreadful, and are these descriptions accurate?

When we say an animal is dangerous or deadly, we are referring to the harm it can cause to humans. The sting of a stonefish is definitely dangerous to humans, but it should be noted that a stonefish never intentionally attacks a human. Most encounters between stonefish and humans are accidental. The venomous spines on the back of a stonefish are purely for its protection from predators. Thus, the stonefish is only dangerous or deadly to humans if they come into contact with it, usually by accidentally stepping on it. So, for humans, the stonefish is indeed dangerous and deadly.

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.

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.

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

• The Stonefish's Sting - Painful & Deadly

Photo: Stonefish Location Map (Australia)

The stonefish are found in shallow tropical waters of the Pacific and Indian Oceans and the Red Sea. Stonefish in Australia live off the coastline, especially in the Great Barrier Reef. It 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 pretend to be something most appropriate to its surroundings, typically an algae-covered rock.

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.

What Do Stonefish Eat? Stonefish Diet

Stonefish Catching Prey Video

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Stonefish are carnivorous predators, eating mainly small fish, crustaceans, and other invertebrates. They are also known to be cannibalistic, consuming smaller individuals of their species if the opportunity presents itself. They are ambush hunters, lying in wait among rocks or sand until prey comes within striking distance (See video).

The stonefish's capture technique is called ‘gape and suck’. 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

During mating season, which typically occurs in warmer months, the female stonefish deposits a layer of large eggs in protected areas such as under rocks or crevices. The male then comes along and releases sperm over them. The male stonefish guard the eggs, protecting them from predators and ensuring they receive adequate oxygenation until they hatch. Once the eggs hatch, the larvae emerge and drift in the water column as part of the planktonic community. As they grow, they undergo various stages of development before eventually settling on the ocean floor and adopting the sedentary lifestyle of adult stonefish.

Stonefish Predators & Threats What Kills Stonefish?

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

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. Their venomous dorsal fin spines are solely for defence. They remain hidden and motionless in their habitat with their venomous dorsal fin spines erect as a defence mechanism. Sometimes, stonefish wash up near the shoreline or on beaches, where humans may accidentally step on them or pick them up. Therefore, any injury suffered by a human is self-inflicted – you ventured into its habitat, stepped on it, or touched it. If you leave the animal alone, you won't get 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. It has 13 spines hidden beneath its dorsal fin, which contain toxic venom. When these spines are pressed, the venom is released, causing immediate and excruciating pain that can last for days. The severity of the outcome depends on the number of punctures suffered from these spines, and symptoms include muscular paralysis, breathing difficulties, and shock. If left untreated, heart failure and death may occur. Stonefish antivenom is the second-most frequently administered antivenom in Australia. While no human deaths from stonefish encounters have been recorded in Australia, fatalities have occurred in other Indo-Pacific areas due to the lack of medical treatment.

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 are stung by a stonefish, wash the wound with cold water, preferably saltwater. Then, apply heat to the wound for 30-90 minutes. Soaking the wound in very hot water (not hot enough to cause burns) is one easy option. Applying heat may help destroy stonefish venom and provide pain relief. Vinegar, which is commonly available on most Australian beaches for jellyfish stings, is also reported to reduce pain. However, these remedies provide temporary relief only, and 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.