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Pacu vs. Piranha: What's the Difference?

Edited by Aimie Carlson || By Harlon Moss || Updated on October 25, 2023
Pacu is a mainly herbivorous fish with square teeth, while piranha is a carnivorous fish with sharp, triangular teeth.

Key Differences

Pacu and piranha are both freshwater fish native to South America, but they have distinct ecological roles and behaviors. Pacu primarily consume plant material and have a reputation for being relatively peaceful, whereas piranhas are known for their aggressive behavior and carnivorous diet.
In terms of physical appearance, pacu have square, straight teeth that resemble those of humans, a feature that aids in grinding plant matter. On the other hand, piranhas possess sharp, triangular teeth, aligned in a single row, perfectly designed for tearing flesh.
While pacu are often larger, with some species growing up to 3 feet in length, piranhas are generally smaller, with the majority of species averaging less than 12 inches in length. However, both are members of the Characidae family.
Pacu are often kept as aquarium pets because of their non-aggressive nature, while piranhas are typically kept by more experienced aquarists due to their tendency to be aggressive and the potential dangers they present.
Habitat distinctions also exist. While pacu can be found in a variety of freshwater habitats, they're often in slower-moving waters. In contrast, piranhas frequent a wider range of habitats, from rivers to lakes, and are often in areas with faster currents.

Comparison Chart


Mainly herbivorous, consuming plants and seeds.
Carnivorous, feeding on fish and meat.

Teeth Structure

Square, straight teeth resembling human teeth.
Sharp, triangular teeth in a single row.


Often larger, up to 3 feet in some species.
Generally smaller, averaging under 12 inches.


Relatively peaceful.
Known for being aggressive.

Common Habitats

Slower-moving waters.
Rivers to lakes, often in faster currents.

Pacu and Piranha Definitions


Often kept as pets in aquariums due to their peaceful nature.
My neighbor has a large pacu in his living room aquarium.


A carnivorous freshwater fish known for its sharp teeth.
The piranha quickly tore into the piece of meat.


A freshwater fish primarily found in South America.
The pacu swam calmly through the aquarium tank.


Has sharp, triangular teeth designed for tearing flesh.
The piranha's teeth are one of its most distinctive features.


A mainly herbivorous species with square teeth.
The pacu's teeth are often mistaken for human teeth.


Native to South American rivers and lakes.
The Amazon River is home to several species of piranha.


A member of the Characidae family.
Just like the piranha, the pacu belongs to the Characidae family.


A member of the Characidae family with a reputation for aggression.
Keeping a piranha requires understanding its aggressive tendencies.


Can grow up to 3 feet in length in some species.
The giant pacu in the public aquarium is a major attraction.


Typically smaller in size, averaging under 12 inches.
The small piranha darted around the tank, displaying its vibrant colors.


Any of several South American freshwater fishes related to the piranha.


Any of various tropical American freshwater fishes of several genera, especially Serrasalmus and Pygocentrus, that have sharp teeth and are known for attacking and feeding on live animals. Also called caribe.


A South American fresh-water fish (Myletes pacu), of the family Characinidæ. It is highly esteemed as food.


(ichthyology) Any of the carnivorous or frugivorous freshwater fish living in South American rivers and belonging to the subfamily Serrasalminae.


Someone who attacks in search of booty


Small voraciously carnivorous freshwater fishes of South America that attack and destroy living animals


What is the primary diet of the pacu?

The pacu primarily consumes plant material.

Are pacus endangered?

Some pacu species face threats, but not all are endangered.

How does the piranha's diet differ?

Piranhas are carnivorous, feeding on fish and meat.

What size do piranhas usually reach?

Piranhas typically average under 12 inches in length.

Is it challenging to maintain a piranha in an aquarium?

Yes, piranhas require experienced aquarists due to their aggressive behavior.

Are pacus aggressive like piranhas?

No, pacus are generally peaceful while piranhas have an aggressive reputation.

Where are pacus found in the wild?

Pacus are native to South American freshwater habitats, often in slower-moving waters.

How dangerous are piranhas to humans?

While piranhas have a fearsome reputation, unprovoked attacks on humans are rare.

How do piranha teeth differ from pacu teeth?

Piranhas have sharp, triangular teeth designed for tearing flesh.

How many species of piranha exist?

There are over 30 recognized species of piranha.

Why are piranhas often portrayed as ferocious in media?

While piranhas can be aggressive, media often exaggerates their danger for sensationalism.

How big can a pacu get?

Some pacu species can grow up to 3 feet in length.

Can you keep a pacu as a pet?

Yes, pacus are often kept as aquarium pets due to their non-aggressive nature.

Are pacus and piranhas related?

Yes, both are members of the Characidae family.

Do pacus attack humans?

Generally, pacus are peaceful and do not pose a threat to humans.

Are piranhas saltwater fish?

No, piranhas are freshwater fish.

Which fish has teeth resembling human teeth?

The pacu has square, straight teeth similar to human teeth.

Are piranhas found in the same habitats as pacus?

While there's some overlap, piranhas frequent a wider range of habitats, including faster currents.

What do pacu teeth look like?

Pacu teeth are square and straight, resembling human teeth.

Can pacus coexist with other fish in an aquarium?

Yes, pacus can coexist with various fish, but tank size and compatibility must be considered.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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