Candiru are small but deadly, with a length of around 1 inch, and are without a doubt a fish you want to avoid at all costs. They are parasitic freshwater catfish that are native to the Amazon Basin and are difficult to spot due to their translucent body.

The goliath tigerfish is known as the most dangerous fish in Africa.  These freshwater fish are found in the Congo River Basin and are highly predatory, feeding on literally anything they can catch.  Goliath tigerfish are incredibly fearsome with their large, protruding teeth and are known as the African equivalent of a piranha.

Wels catfish are huge freshwater fish that can reach an incredibly 16 feet long.  These giants are found in lakes and rivers in Europe and are easily recognized by their broad, flat heads and huge mouths.  Wels catfish eat a range of worms, insects, fish, rodents, frogs, and birds. 

Despite looking more like a snake, moray eels are actually fish and are incredibly dangerous.  There are around 200 species of moray eels worldwide and although most live in the sea, some are found in freshwater.  Most moray eels can reach 5 feet and don’t have pectoral fins which some people mistake for snakes. 

Boxfish are very similar to pufferfish (next on our list), although not quite as lethal.  Their size ranges between 10 and 24 inches, depending on the species, and they usually inhabit rocky and coral reefs in the Indian, Pacific, and Atlantic oceans.  They are distinguished by their box-shaped bodies and honeycomb patterns on their skin.

Easily one of the most dangerous fish in the world is the pufferfish.  There are more than 120 species of pufferfish and they can range in size from 1 inch long to more than 2 feet.  Pufferfish are found in most tropical and subtropical waters and they inflate into a ball when they are threatened or disturbed, hence their name. 

No list of deadly fish would be complete without the great white shark.  Great white sharks are the most notorious sharks and are responsible for the highest number of unprovoked attacks on record.  With around 300 teeth and an estimated bite force of around 18,000 newtons, the great white is a fierce predator.

Oceanic whitetips inhabit tropical seas around the world and are distinguished by their white-tipped fins.  Although the great white shark, tiger shark, and bull shark have far more recorded attacks on humans, the oceanic whitetip is generally believed to have killed the most people.  

Lionfish are incredibly venomous fish that are native to the Pacific Ocean, although they have now invaded many other oceans.  They reach around 18 inches long and are characterized by their bright colors.  Lionfish can have red, white, or black bands and have spiky fin rays which are venomous.  

The deadliest fish in the world is the stonefish, which has some serious ability to cause harm!Stonefish are around 14 to 20 inches long and the same in width due to their extremely wide pectoral fins.  They are found in tropical waters – including the Indian Ocean, Pacific, Red Sea, and the Great Barrier Reef.