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Science & Nature • Marine Life

Pufferfish

Pufferfish are a group of fish in the family Tetraodontidae, known for their ability to inflate their bodies as a defence against predators.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

Pufferfish are a group of fish in the family Tetraodontidae, known for their ability to inflate their bodies as a defence against predators. They are found mainly in tropical and subtropical waters, with some species living in brackish or freshwater environments. Many species contain tetrodotoxin, a potent toxin that makes them dangerous to eat if not prepared properly.

Classification and diversity

Pufferfish belong to the family Tetraodontidae, which includes more than 120 known species. They are found in a wide range of sizes, body shapes, and colour patterns.

Habitat and distribution

Most pufferfish live in tropical and subtropical marine environments. Some species also inhabit brackish waters and freshwater systems.

Defence and toxicity

Pufferfish defend themselves by inflating into a larger shape and, in many species, by relying on tetrodotoxin. This toxin can be lethal to predators and humans.

Diet and feeding

Pufferfish feed mainly on invertebrates and algae. Larger species can crush hard-shelled prey such as clams and mussels with beak-like teeth.

Key facts

  • There are more than 120 species of pufferfish worldwide.
  • Pufferfish can quickly inflate by taking in water or air, making themselves harder to swallow.
  • Many species contain tetrodotoxin, which is highly poisonous to humans and other animals.
  • Most pufferfish live in tropical and subtropical ocean waters, but some species live in brackish or freshwater habitats.
  • Pufferfish are typically scaleless and often have rough or spiky skin.
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Canadian context

Pufferfish are relevant to Canadian readers mainly through marine biology, aquarium keeping, seafood safety, and public education about tetrodotoxin poisoning. They are not native to most Canadian waters, but occasional range shifts and sightings can interest researchers and coastal communities.

Frequently asked questions

What is a pufferfish?
A pufferfish is a fish in the family Tetraodontidae, best known for inflating its body when threatened.
Why do pufferfish inflate?
Inflation is a defence mechanism that makes the fish appear much larger and harder for predators to eat.
Are pufferfish poisonous?
Many pufferfish species contain tetrodotoxin, a powerful poison that can be deadly to humans.
Where do pufferfish live?
Most live in tropical and subtropical seas, but some species occur in brackish or freshwater habitats.
How many species of pufferfish are there?
Sources report more than 120 species worldwide.
What is fugu?
Fugu is the Japanese name for pufferfish, especially when prepared as a delicacy by licensed chefs.

References

  1. Ocean Conservancy — https://oceanconservancy.org/blog/2022/08/01/fun-facts-pufferfish/
    Supports: Number of species; habitat range; general pufferfish facts
  2. National Geographic — https://www.nationalgeographic.com/animals/fish/facts/pufferfish
    Supports: Scientific family; toxicity; habitat; size; diet; species count
  3. National Geographic Kids — https://kids.nationalgeographic.com/animals/fish/facts/pufferfish
    Supports: Toxicity; fugu; habitat; vulnerability; size
  4. National Marine Sanctuary Foundation — https://www.nationalmarine sanctuaryfoundation.org/blog/sea-wonder-pufferfish/
    Supports: Habitat, diet, inflation, toxins, species count