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Pufferfish on reef

Things you never knew: 7 Facts about Pufferfish

Pufferfish are seen widely across our dive sites and are not often considered to be a “special” find but we hope that with these 7 facts about Pufferfish you will recognise how unique and incredible this family of fish really is. With so many species here in North Sulawesi identifying individual species is always fun.

1. How Many Species?

Pufferfish are in the family of Tetraodontidae which encompasses around 120 different species. While we don’t have them all here in North Sulawesi we do have a large number of species which can be found at most of our dive sites. The more commonly seen species here are the black spotted puffer, giant puffer and the map puffer.
Pufferfish are characterised by their long tapered bodies, rounded heads, prominent lips and large stomachs. Despite the size of their stomachs it’s surprisingly not used during the digestion process!


Arothron stellatus or Star Puffer

Larger puffer fish species often attract cleaner fish

2. Why do they “Puff up?”

When pufferfish feel threatened they can actually “puff up” to three times their original size. Many pufferfish are brightly colored and they are not fast swimmers which makes them easy targets to predators looking for an easy meal. When they puff up they take air into their stomachs to look larger but also to make themselves into a round, ball-like shape which looks difficult to eat. Some pufferfish also have spines which stick out like needles when they are puffed up which again makes them look like a challenging bite!

3. Docile but Deadly

Pufferfish may look slow and steady and even “cute” when swimming around on the reef but these are one of the most deadly species of fish. When pufferfish inflate they release a dangerous chemical on their skin known as TTX (tetrodotoxin). Did you know that TTX is 100 times more toxic than cyanide? TTX is a neurotoxin which damages the nervous system in such a way that it causes numbness, paralysis and within a few hours, heart and lung failure and death. Signs of TTX poisoning in humans include numbness in the lips and tongue, dizziness, nausea, mobility problems, turning blue and complete paralysis. One pufferfish carries enough TTX in its liver to kill 30 human adults which makes it the second most deadly creature on the planet, after poison dart frogs. Isn’t that one of the most fascinating facts about pufferfish?


(Canthigaster valentini) Black Saddled Toby

Even the smallest of species are characterised by distinct shaped snouts

4. Masters of Disguise

Octopus are not the only chameleons of the sea, pufferfish can change color by making themselves lighter or darker to match their environments and just like chameleons they can move their eyes independently so their left eye and right eye are looking in different directions – meaning they can look at two different things at the same time. This is a great defence mechanism which enables them to see predators coming from different directions and to swim away or inflate in plenty of time.

5. Unique Dentistry

Did you know that the Greek word for the number four is “tetra” and that the Greek word for teeth is “odous”? Put them together and we have Tetraodontidae! Their unique dental arrangement is what sets them aside from other fish; they have two upper teeth and two lower teeth which give them a beak-like appearance. Their teeth are constantly growing so to keep them in check they chow down on shell fish, hard corals, algae that grows on rock and bottom dwelling critters.


blackspotted puffer (Arothron nigropunctatus)

Pufferfish have 4 teeth, 2 upper and 2 lower

6. My Nest is My Castle

Some species of pufferfish are known to build nests on the reef. One such species, which is found here in North Sulawesi, is the white spotted puffer. The male pufferfish will make a round shaped “nest” in the sand which can be up to 6 feet in diameter. The nest is made to attract females who will “lay” their eggs in the nest for the male to fertilise. Each time a white spotted puffer is ready to breed it will make a new “nest”.


Video Courtesy of BBC Earth Unplugged Series


Male masked pufferfish, which are also found across our dive sites here, make nests made from their sperm as it creates a hiding place for them and the smell discourages predators! This must be the weirdest of the 7 facts about Pufferfish.

7. Healing and Protecting

While TTX is known to be one of the most potent toxins in the world it has also been found to have anti-cancer properties and female pufferfish also pass on small amounts of TTX to their eggs to protect them from predators!


If you’d like to know more facts about pufferfish or the the species we have here, then come and see them for yourself, contact us at: [email protected]. You’ll experience everything from vertical walls in Bunaken to sloping reefs and pinnacles in Bangka through to some of the world’s rarest and most unusual marine life in Lembeh. To learn more about out how to explore our 3 phenomenal areas in one trip with our Passport to Paradise.


Dive, Snorkel and Explore More with us in beautiful North Sulawesi.

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