Pufferfish Facts

10 Pufferfish Facts About The Inflating Creature

Exploring our pufferfish facts will show us intriguing truths about these spiky fish. From their inflating bodies for self-defense to their incredibly toxic organs that can kill humans, we included all the essentials to enlighten you with these fish.

Belonging to the scientific family Tetraodontidae, around 120 individual species of pufferfish are distributed widely across the world's oceans, inhabiting subtropical ocean waters.

Despite their toxicity, pufferfish are a delicacy in some cultures. And a particular predator is immune to its toxins. Are you curious? Get to know their effects on other animals and their impact on our lives as we dive deep into these unique sea creatures.

Before the article starts, save these fish facts to learn more about other unique fish! 

10 Must-Read Pufferfish Facts

inflated pufferfish
Photo by Jeffry Surianto on Pexels

1. Pufferfish expand for self-defense.

Pufferfish can transform into a balloon-like shape when under threat. This transformation is a specialized defense mechanism that has evolved over many generations.

The pufferfish takes in a large amount of water–or, in some cases, even air–toward their stretchy stomachs, causing them to inflate to several times their average size. Besides inflating their body, this transformation drives their spines to stand on end, making them unappealing to any predator attempting to consume them. 

However, it's important to note that this inflation process is a last resort for the pufferfish, only used when all other escape attempts have failed. Despite the benefits of this defense mechanism, it also stresses the puffer fish's body.

Fun fact: Did you know that among the wide variety of bony fish, the pufferfish has the distinctive ability to blink or close its eyes? They achieve this by sinking their eyeballs deep into their sockets and puckering the surrounding skin together, a trait yet unseen in other bony fish species.

2. Pufferfish are master swimmers.  

closeup pufferfish
Photo by David Clode on Unsplash

Pufferfish are skilled swimmers despite their circular shape. They do not have tail fins, but their small pectoral fins enable them to navigate complex coral formations and underwater crevices. While not the fastest swimmers, they are mobile enough to evade predators and adapt to water currents.

Moreover, the pufferfish also relies on its dorsal and anal fins; the latter works like a rudder, providing stability and direction while navigating the depths. The pufferfish's body undulates while its fins rhythmically flap.

3. Pufferfish can live in freshwater.

While most pufferfish live in subtropical ocean waters, some pufferfish species live in freshwater rivers worldwide. For example, the Freshwater Giant Puffer, or mbu pufferfish, lives in the Congo and Malagarasi Rivers in Africa and Lake Tanganyika.

This sizable species often reaches an impressive length of up to 67 centimeters (26 inches) in its natural habitat. On the other hand, the diminutive Pygmy Puffer (Carinotetraodon travancoricus), holds the title for the smallest pufferfish, measuring a mere 1 inch (2.5 centimeters) in length when fully grown.

This freshwater species can adapt well to river environments, which sets it apart from its saltwater counterparts. Furthermore, there are a few puffer fish found in brackish water4

Additionally, the Nile River is home to the Fahaka pufferfish. The Nile provides a suitable habitat for flourishing Fahaka pufferfish.

Moreover, many home aquarium enthusiasts keep freshwater pufferfish, such as dwarf pea puffers, imitator puffers, redeye puffers, crested puffers, fang's puffers, and emerald puffers. These fish have unique behaviors and vibrant presence, adding an element of the wild to your fish tank. (Remember that a large puffer fish will need a 100-gallon tank or bigger.)

4. Pufferfish are edible but deadly.

Photo by Starseed on Wikimedia Commons CC BY-SA 3.0 (Cropped from original)

Enter a restaurant in Japan, and you may see pufferfish called "Fugu" on the menu. This species offers delectable flavors and potential danger; part of the appeal is your sense of adventure, daring you to try a dish that can kill you. 

Preparing Fugu is an exact and intricate process, requiring the expertise of a skilled chef. While potentially lethal, the pufferfish can become a delicacy when prepared correctly. The fish contains tetrodotoxin, an extremely toxic substance approximately 1,200 times more deadly than cyanide. The toxin comes from marine bacteria present in their diet2.

It appears in the fish's liver, ovaries, intestines, and skin. Ingesting it can result in severe paralysis or death. Just one puffer fish has enough toxins to kill around 30 humans and has no known antidote. 

Trained chefs use precise knife work to remove the toxic parts carefully to prevent contaminating the edible parts. Once the harmful substances are gone, you can enjoy the delicate and unique flavor of the pufferfish. Some gastronomes relish this flavor despite the risk.

Humans have the means to make this fish edible. But how about in the wild? The following facts about puffer fish talk about the effects of their toxin on other animals.

5. Only sharks are safe from the puffer fish’s toxin.

While the pufferfish contains toxins that could kill other fish, the tiger shark is immune to its tetrodotoxin and sees it as a routine meal. The tiger sharks' immunity to the toxin is still a mystery. 

However, scientists speculate it could be a unique adaptation in the shark's nervous system. Still, rarely, the poison affects sharks, paralyzing them for a few moments after eating the fish. Despite the paralysis, tiger sharks typically do not die from eating a pufferfish.

Before moving on to the rest of the article, did you know there are various pufferfish species, such as the dwarf puffer fish (the smallest puffer fish) and the stellate puffer fish (the largest puffer fish)? 

6. Dolphins seem to "get high" off pufferfish.

inflated spiky fish
Photo by Stelio Puccinelli on Unsplash

A BBC footage first observed a peculiar interaction between dolphins and pufferfish. The mammals intentionally bother the fish, causing them to release their toxins. The dolphins then appear to inhale the toxins, float just below the surface, and observe their reflections. Some experts speculate that dolphins may experience a sense of intoxication similar to that of humans.

These mammals are genuinely playful! Know more about them with our dolphin facts.

7. Pufferfish draw to attract mates.

Puffer fishes, like the Torquigener albomaculosus species, observe unique mating behaviors. For example, male pufferfish of this species create intricate geometric designs on the ocean floor to attract potential mates. They craft these patterns over a week; these designs showcase the male's artistic prowess and protect the eggs from ocean currents.

Interestingly, the design's complexity indicates the male's strength and age. Older and stronger males create the most intricate patterns to show their vitality. In 1995, divers off the coast of Japan first observed this behavior, an example of how wild animals will go to great lengths to ensure the survival of their species.

8. Pufferfish live a long life.

masked pufferfish
Photo by Francesco Ungaro on Pexels

Pufferfish enjoy a long lifespan, with some species living up to ten years in the wild. Their diet and growth rate contribute to their longevity. Their omnivorous diet, comprising algae, small fish, and invertebrates, provides them with a comprehensive nutrient palette. Moreover, they can eat hard foods because of their beaks.

Pufferfish grow slower than other marine species, which could account for their remarkable lifespan. In captivity, pufferfish can live up to 15 years.

Driven by human curiosity, the pufferfish fact below shows the possible application of their toxin in medicine.

9. Scientists are studying pufferfish toxin for medicinal use.

The pufferfish tetrodotoxin (TTX) blocks nerve signals, attracting the attention of researchers studying pain management. Tetrodotoxin blocks the passage of sodium ions in neurons, effectively halting nerve signal transmission. This unique ability has posed several exciting possibilities for treating severe pain.

However, exploiting tetrodotoxin for medicinal purposes is a complex process. Early clinical trials have shown its potential to combat chronic pain associated with cancer and nerve damage diseases1. Nonetheless, our knowledge of this toxin is still in the beginning stage.

Since excessive tetrodotoxin can cause paralysis or death, the primary challenge is to achieve a safe dosage and delivery mechanism, requiring precision and care. Despite these challenges, the potential benefits of tetrodotoxin are significant enough to continue exploration.

10. Pufferfish face various threats.

Despite their wide distribution, these animals face various global threats that challenge their survival, such as habitat loss, pollution, and overfishing. One of these threats is habitat loss, which occurs due to coastal development and deforestation. 

In addition, climate change causes rising sea temperatures and ocean acidification. In other words, the water becomes too acidic for marine life to thrive, damaging the coral reefs where pufferfish live and eat3. These reefs soon become barren and bleached environments, which could lead to the fish's extinction. 

Moreover, pollution, particularly plastic debris, is a significant threat to pufferfish worldwide. Like many other fish, they often eat floating garbage, which can cause severe internal injuries and even death. 

Remember to share these pufferfish facts to increase appreciation and awareness for these spiky sea creatures.

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Hagen, N. A., Fisher, K. M., Lapointe, B., du Souich, P., Chary, S., Moulin, D., ... & Ngoc, A. H. (2008). An open-label, multi-dose efficacy and safety study of intramuscular tetrodotoxin in patients with severe cancer-related pain. Journal of Pain and Symptom Management, 36(3), 262-272.


Noguchi, T., Onuki, K., & Arakawa, O. (2011). Tetrodotoxin poisoning due to pufferfish and gastropods, and their intoxication mechanism. ISRN toxicology, 2011, 276939.


Hoegh-Guldberg, O., Mumby, P. J., Hooten, A. J., Steneck, R. S., Greenfield, P., Gomez, E., ... & Hatziolos, M. (2007). Coral reefs under rapid climate change and ocean acidificationscience318(5857), 1737-1742.


Ebert, K. (2001). Die Kugelfische Des Süß- und Brackwassers (The Puffers of Fresh and Brackish Waters). AQUALOG Verlag.

Mike is a degree-qualified researcher and writer passionate about increasing global awareness about climate change and encouraging people to act collectively in resolving these issues.

Fact Checked By:
Chinny Verana, BSc.

Photo by David Clode on Unsplash
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