13 Most Dangerous Fish, Eels and Sharks

1. Stonefish

The stonefish holds the title of the most venomous fish in the world. Found in the Pacific and Indian Oceans, it has venomous spines along its back that can deliver a painful, sometimes fatal, sting if stepped on or provoked.

The venom can cause extreme pain, tissue damage and even death if left untreated. Its ability to camouflage as a rock makes it especially dangerous for unsuspecting swimmers.

2. Puffer Fish

The puffer fish, or fugu, is considered the most poisonous fish in the world. Found primarily in the Pacific and Indian Oceans, puffer fish contain tetrodotoxin, a neurotoxin that's lethal to humans. This poison can cause paralysis and death if consumed in even small amounts.

In some cultures, puffer fish is a delicacy, but improper preparation can lead to fatalities, making this fish one of the deadliest in the ocean.

3. Lionfish

The lionfish is a strikingly beautiful but deadly predator with elongated dorsal fin spines that can inject venom into anyone who gets too close. Found in the Pacific and Indian Oceans, lionfish venom can cause extreme pain, nausea and difficulty breathing, although fatalities are rare.

However, their spread into non-native regions has made them a dangerous invasive species in some parts of the world.

4. Barracuda

Barracudas are long, fast fish with sharp teeth that can cause serious injuries to humans. They are known for their aggressive behavior, especially when they feel threatened.

Barracudas have been known to attack humans, though such encounters are rare. However, their speed and sharp teeth make them a force to be reckoned with in the water.

5. Goliath Tigerfish

The Goliath tigerfish is one of the finest game fishes in Africa, but it's also one of the most dangerous. With its massive size and razor-sharp teeth, this fish has been known to attack humans in rare cases.

Found in the Congo River and Lake Tanganyika, the Goliath tigerfish is feared by locals for its aggressive behavior and powerful jaws.

6. Piranha

Piranhas have developed a fearsome reputation for their sharp teeth and aggressive feeding habits. While most piranha species are not dangerous to humans, some, like the red-bellied piranha, can attack in large groups, especially when food is scarce.

Though fatalities are extremely rare, piranha bites can still hurt a great deal.

7. Surgeonfish

Surgeonfish are known for the sharp, scalpel-like spines located near their tail, which they use for defense.

While they aren't known for attacking humans, accidental contact with these spines can result in deep wounds, and in some cases, the spines may carry venom. These fish are generally peaceful but can become dangerous when cornered or threatened.

8. Triggerfish

Triggerfish are brightly colored fish found in tropical waters, and while they aren't large, they can be surprisingly aggressive.

Known for defending their nesting sites, triggerfish have sharp teeth and a powerful bite that can cause serious injuries if a diver or swimmer gets too close. Their territorial behavior makes them a potentially dangerous fish, despite their small size.

1. Great White Shark

Great white sharks are perhaps the most famous deadly fish, thanks to their portrayal in movies and their sheer size. These sharks have razor-sharp teeth and are responsible for the highest number of unprovoked shark attacks on humans.

While great white sharks don't typically target humans, their size, strength and bite force can cause severe injuries or death when they do attack.

2. Tiger Shark

Tiger sharks are dangerous predators known for eating just about anything from fish to sea turtles and even garbage.

These sharks are responsible for a significant number of human fatalities due to their powerful bites and sharp teeth. Tiger sharks are especially dangerous because they often swim in shallow waters, where they can come into contact with humans.

3. Bull Shark

Bull sharks are known for their aggressive behavior and willingness to swim in shallow waters, increasing their likelihood of coming into contact with humans.

Found in both saltwater and freshwater environments, bull sharks have sharp teeth and can attack humans without provocation. They are responsible for numerous fatal shark attacks, making them one of the most dangerous fish species in the world.

1. Electric Eel

While not technically an eel, the electric eel is one of the most potentially dangerous fish in freshwater. These fish can generate up to 600 volts of electricity to stun prey or defend themselves from predators.

Although electric eels don't attack humans regularly, their shocks can cause serious injuries, and in some cases, multiple shocks have led to fatalities, particularly if the person is in the water and unable to escape.

2. Moray Eel

Moray eels are known for their aggressive behavior and sharp teeth, which can deliver a powerful bite if provoked. These eels typically hide in crevices and attack when disturbed, often inflicting deep wounds with their razor-sharp teeth.

While they don't usually seek out humans, their aggressive defense tactics make them one of the most potentially dangerous fish species in the ocean.

We created this article in conjunction with AI technology, then made sure it was edited and fact-checked by a HowStuffWorks editor.