17 Most Dangerous Fish in the Pacific Ocean

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By Jonathan Trent

When you’re sitting on a tropical beach overlooking the Pacific Ocean, you can be forgiven for thinking everything looks picturesque. However, under the ocean’s surface lies a hoard of creatures capable of causing serious harm to humans. Here are 17 of the most dangerous fish in the Pacific Ocean.

Reef Stonefish

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The reef stonefish is the most venomous fish in the world and can be found in the shallow waters of the Indo-Pacific Ocean. Its thirteen highly venomous spines on its dorsal fins can puncture the soles of boots, potentially causing paralysis or death if stepped on. The stonefish are also very well camouflaged, making them more sinister.

Puffer Fish

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They may be one of the cutest fish species in the Pacific Ocean, but puffer fish contain enough poison to kill 30 humans. The poison is called tetrodotoxin, which, according to BBC Wildlife, binds to its victim’s nerve cells, causing paralysis and death by suffocation.

Moray Eel

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Moray eels, found in the South Pacific, have a surprisingly high bite force of up to 700 pounds per square inch, which can cause you to lose a limb if bitten. To put this into context, police dogs have a bite force of around 240 pounds per square inch.

Great White Sharks

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Possibly the most famous shark, the great white is responsible for more human deaths than any other type. Over the years, great whites have been responsible for many unprovoked attacks on humans, with CBS News suggesting that this is a result of attacking unfamiliar objects to test their potential as food.

Yellow Box Fish

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Yellow box fish don’t look at all threatening with their polka dot patterning but the fish, found in the Eastern Pacific, pack a peculiar punch. When stressed, the box fish will release poisonous proteins from its skin, which prevents its predator from breathing. 

Flower Urchins

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Flower urchins may look beautiful, but they pack a brutal amount of venom in the petal-esque cups that line their bodies. They are the most dangerous urchins in the ocean, with those unfortunate enough to step on them at risk of paralysis and respiratory issues.

Blue-Ringed Octopus

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The venom that a blue-ringed octopus can emit is the same as that of a puffer fish: tetrodotoxin. It is neurotoxic and blocks the transmission of nerve impulses, preventing muscle contraction. Tetrodotoxin is said to be 1000 times more toxic than cyanide.

Bull Sharks

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While they aren’t responsible for as many human deaths as great white sharks, bull sharks are among the three most aggressive shark species. As National Geographic reports, bull sharks aren’t afraid to linger around shallower waters heavily populated by humans.

Pacific Electric Rays

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Unlike most fish, Pacific electric rays will approach their predators if they feel threatened, bolstered by the realization that they can emit up to 45 volts of electricity into their attacker. This may not kill a human, but it will certainly knock them down. 


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In a stingray attack, it won’t be venom that’s killing you, but instead, the puncture wounds that you can obtain from their tails. Stingray attacks on humans are very rare but were shot to the forefront of public knowledge after the death of beloved conservationist Steve Irwin in 2006.

Crown of Thorns Starfish

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The crown of thorns starfish is aptly named, featuring an array of spikes that can easily puncture the skin of a human. The neurotoxins on their spines can cause feelings of nausea, lasting for around a week. There’s no wonder why the species is considered the most dangerous starfish in the world.

Box Jellyfish

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Stings from the tentacles of box jellyfish can result in cardiac arrest and death within minutes. The tentacles will be tough to avoid, as they can measure up to three meters in length. With 24 eyes and an ability to move faster than most jellyfish, box jellyfish are a truly terrifying species.


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Lionfish are truly stunning creatures adorned with an array of dorsal fins and beautiful white and maroon striped bodies. Despite not being as venomous, they hail from the same family as the reef stonefish, with similar stout spines spread around their bodies.


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Although not known for attacking humans, barracudas are likely to attack if they see the reflection of something shiny, such as jewelry or a fishing knife, mistaking them for fish. Barracudas are highly skilled predators due to their size and top speeds of 36 mph, as per Oceana.

Oceanic White-Tip Sharks

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Oceanic white-tip sharks tend to get off lightly in a reputational sense, with most of the human fear of sharks being attributed to great whites or bull sharks. However, these undersea monsters are said to have attacked survivors of shipwrecks and plane crashes, responsible for many unrecorded deaths.

Giant Trevally

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The Giant Trevally may cost you a finger or two, but not by design. If you were to feed a giant trevally, which can measure up to around six feet long, it may mistake your fingers or hand for food and take a bite.


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You’d have to be incredibly clumsy if you were to succumb to an injury from a triggerfish. However, they do possess a rather strong bite, as their teeth are designed to be able to crush corals. They’re unlikely to attack unless you come too close to a female triggerfish around her nest.