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Stonefish, Florida’s Deadly Venomous Fish (Huge Guide!)

Stonefish - is it a killer or just very capable of defending itself?

Stonefish are closely related to the scorpionfish, also known as the lionfish here in Florida. Stonefish are capable of injecting strong venom through their short venomous barbs which can cause medical emergency and even death within a couple hours of envenomation.

In 2010 a Japanese diving instructor died within 2 hours after stepping on one in shallow water1.

Stonefish are known as the world’s most deadly venomous fish. The last death in Australia from the stonefish occurred in 1915. In Japan in 2010. Antivenom has been developed that greatly reduces deaths.

Here we tell you everything you need to know to avoid this deadly fish.

What Is a Stonefish?

A bottom dwelling blob of a fish that looks more like a stone or rock or coral than it does a fish.

In the Scorpaenidae family, the same as the lionfish, the species name is Synanceia horrida. Stonefish venom is stronger than lionfish and their venomous barbs are thicker and more efficient for injecting venom.

Where Do They Live?

Stonefish live in the ocean in shallow water on the bottom and on coral reef and rocks. They are also known to swim up river and live a few hundred yards up into freshwater.

What Happens with a Stonefish Sting?

Usually someone steps on one hidden in shallow water in their bare feet. The venomous spines (there are 13 of them) inject venom in direct proportion to how hard the pressure is on the spines, so if you hit it hard more venom will be injected than if you just barely touch it.

The venom has a strong neurotoxin (nerve toxin) – trachynilysin and a cardiotoxin (heart toxin) – cardioleputin that act together to render the person virtually helpless.

The strong venom acts quickly to cause intense (excruciating) pain and swelling. Your entire arm or leg will swell up in minutes. You will not be able to take care of yourself if envenomated, you need help quickly.

Symptoms of Stonefish Stings

  • intense pain
  • swelling and redness
  • paralysis
  • heart rhythm problems
  • necrosis (dead tissue) at the sting site
  • heart stoppage
  • low blood pressure, shock
  • nausea
  • many other symptoms are possible

What Should I Do If Stung by a Stonefish?

When you are stung, Immediately notify other people that you have been stung and tell them to take you to the hospital as fast as possible.

The venom stonefish inject is neurotoxic and affects the nerves. The nerves control our muscles and mind and are part of the electrical system in our bodies.

The venom has the potential to disrupt breathing and heart rhythm and beating.

You won’t be able to do anything for yourself. You must rely on others to help you reach the hospital.

At the hospital, victims will likely receive a tetanus shot, an antibiotic covering marine organisms, lidocaine injections for pain, hot water immersion treatment, and constant monitoring for a couple of days.

What is the Home Cure for a Sting?

If you are unable to reach a hospital, prepare some hot water – as hot as you can stand, around 113°F (45°C) and soak the affected area for 30-90 minutes.

It’s crucial that the water is hot and yet not going to give you any kind of serious burn.

The hot water makes the venom inert. It can take a few days of soaking in hot water to render the venom harmless.

Do Stonefish Attack People?

No, stonefish do not attack people and only inject venom when touched or stepped on.

Like most small animals, stonefish do not target people as prey or enemies without provocation. They don’t even use their venomous spines to attack fish.

They use the spines only as a defense mechanism to stay alive, mostly to avoid bottom dwelling sharks. So they only use the spines when a predator is too close or aggravating them.

How Do People Get Stung by Stonefish?

Stepping on stonefish accidentally or foolishly picking one up are the primary ways people are stung and envenomated.

These fish are very good at camouflaging themselves and you may not even see them while snorkeling or walking on the beach or in the water.

They lay on the bottom or in coral reefs and are easily stepped on. Some divers and snorkelers are able to spot them easily.

Once you know what they look like it stays in your mind and you see more of them.

Stonefish can live outside water, on the beach and in tide pools for 24 hours as long as their skin stays wet. People have stepped on them on the beach sand and in shallow waters frequently.

What Does a Stonefish Look Like?

Their camouflage allows them to stay still and ambush smaller fish that get too close. Even fish can’t tell it is there, they are nearly invisible and blend in with their surroundings perfectly.

They look like rocks or a piece of coral. They are bumpy and brown and multicolored, but generally dark colors. Algae grows on their skin and helps to hide this fish. In Australia one kayaker found one in the shallows and scooped it up with his paddle.

The fish looked like a pile of manure. See photo.

A deadly stonefish balanced on a kayak paddle in Australia.
Deadly stonefish looks like a blob of brown coral or feces.

Do Stonefish Have Any Natural Predators?

Moray and other eels are quite skilled at eating them and avoiding their venomous spines. Sharks on the bottom of the ocean will sometimes try their luck with eating one.

How Can I Avoid Stonefish in Florida?

You can avoid stonefish by always wearing thick soled diving shoes while in the shallow water, especially near coral reefs.

The spines are not that strong that they go through a thick rubber sole, but they easily pierce bare feet and unprotected skin.

You can avoid them by never picking up marine life when you don’t know what it is. Some people have this fascination with touching and holding bugs and other wildlife like venomous snakes and jellyfish and sometimes it sends them to the emergency room or morgue.

How Many People Die Each Year from Stonefish Stings?

Very few. The reason is, we now know that hot water destroys the venom potency and there is antivenom in Australia that is given for severe cases. In Florida, I cannot find even one case of death attributable to this fish. I think the danger is blown out of proportion.

Envenomation can be serious, but and immediate hospital visit should take care of you and a sting will likely not put you in a life-threatening situation.

Can a Stonefish’s Venomous Barbs Pierce a Shoe?

Yes, a thin foam or rubber shoe. Wear something thicker and not very flexible to prevent the spines from penetrating to your feet.

Can Stonefish Be Consumed as Food?

Yes. Removal of the venomous dorsal spines makes the fish edible for humans as sashimi or can be baked, broiled, boiled, steamed, or fried as other fish and eaten.

Please watch this somewhat helpful video about how to safely prepare stonefish for human consumption. I looked at 13 videos and none of them were great.

Does It Taste Good?

Yes! It is considered a delicacy (especially delicious) in Asian countries. The flesh is white and flaky and tastes great however it is cooked. Sashimi is a favorite way to enjoy this deadly fish in Japan.

Watch this Short Clip About the Stonefish (Video)

DEADLIEST FISH IN THE WORLD: Stonefish | Oceana

Summary – Crucial Things to Remember About Stonefish

The danger of stonefish is somewhat overstated in the literature. There are very few deaths worldwide, and the stonefish is certainly not the most deadly fish in the world.

That title would belong to one of the shark species for sure. They are said to be the most deadly venomous fish species.

Stings can be avoided by knowing where you are walking in shallow water and even at the beach. Wearing thick rubber soled diving shoes can help if you step on or near one of these venomous fish.

The venom is rendered harmless over time with the application of hot water to the site and affected limb.

This may need reapplication over and over for a couple days to fully treat the sting victim.

Stone fish are delicious when cooked or as sashimi. Their venomous spines contain nearly all of the toxin, so when removed the fish is able to be eaten.

Also, please note that venomous toxin is not the same as ‘poisonous’. Venomous toxins are generally OK to eat because your digestive system takes care of the venom and it doesn’t cause harm.

If something poisonous is eaten, the digestive system has no effect and it can cause great harm.

This is true of snake venom, stonefish venom, and any venom.

Do you know anyone who has ever seen a stonefish or was stung by one? Tell us the story!

More Reading

Here’s a story about when I stepped on the venomous barb of a stingray. Here’s one about my box jellyfish envenomation. And here is an article about Lionfish – a close relative of the stonefish.

Citations

  1. Stars and Stripes. Okinawan Diver Dies from Stonefish Sting. August 6, 2010. Chiyomi Sumida, David Allen.