Pufferfish are cool but deadly: Lifeform of the week
Image via Jeffry Surianto/ Pexels.
Pufferfish may be used as comic relief in cartoons, swelling to three times their size when scared. But pufferfish are deadly. The poison in a single pufferfish can kill up to 30 humans. Yet in some countries, the careful preparation of this fish makes it a delicacy.
What do pufferfish look like?
Pufferfish have the shape of an ordinary fish when calm, but when they feel attacked, their extremely flexible stomachs swell with air or water. Additionally, most pufferfish have sharp spines all over their bodies, except for the eyes and mouth.
There are more than 120 species of pufferfish worldwide, and each has different morphological characteristics. But in general, you can observe patterns such as stripes and dots. As for color, pufferfish can be gray, blue, yellow, brown and white. It is curious to see the large number of interesting combinations they present.
The size of these fish varies depending on the species. The smallest in the world is the dwarf or pygmy pufferfish, which does not even reach 1.2 inches (3 cm) in length. The largest is the giant freshwater pufferfish, which is approximately 26 inches (67 cm) long.
Another distinctive feature is their four teeth, located right at the end of the mouth, two above and two below. These teeth never stop growing, so they must wear them down. To do so, they have a hard diet.
Where do they live?
You will never find them in cold waters. Pufferfish live in tropical and temperate waters around the world, and generally in shallow waters, no deeper than 980 feet (300 meters). Most species are saltwater, although there are some freshwater species.
These fish live near the coast, and their habitat consists of areas covered with algae, aquatic plants and coral reefs. In the case of freshwater species, you can find them in rivers, streams and swamps.
How do pufferfish swell?
Pufferfish live in places frequented by larger animals. Unfortunately, pufferfish are neither agile nor fast, which is why they developed a good defense.
Pufferfish change considerably when they’re in a state of alert. At rest, they have a rounded and elongated body with a slight bulge in the lower or ventral area. When they are scared, their stomachs inflate with water if they are submerged, or with air if someone has taken them outside. They form a balloon that in most cases is protected by pointed spines. They can reach 3.3 times their resting body volume.
The pufferfish does not have scales, but it does have rough and flexible skin so that it can inflate easily. In addition, depending on the species, they are covered in different sized spikes. However, not all pufferfish have protective spines, and if they do, sometimes they are not that noticeable.
It is normal for these fish to flee when they feel threatened. They only resort to this strategy when there is no other choice, because swelling expends a lot of energy. They can remain inflated for around 15 minutes.
Pufferfish are extremely poisonous
Pufferfish have two lines of defense. They can swell up to look bigger, and in many cases possess sharp spikes, but most pufferfish are also extremely poisonous. Plus, the deadly poison has an unpleasant taste. So, the pufferfish is unappetizing both to the eye and to the taste of its predators.
They are poisonous because they contain tetrodotoxin, a deadly neurotoxin that’s much stronger and faster-acting than cyanide. In fact, pufferfish are one of the most dangerous fish on the planet with this toxin that is 1,200 times more powerful than cyanide. Thus, they can kill not only animals but humans as well. One pufferfish contains enough poison to kill up to 30 adult humans.
Poisonous but edible?
Despite being extremely dangerous, there are humans who find its meat a delicacy. This poisonous fish is popular in Japan. But it’s only prepared by specialists. Chefs possess a special license that is difficult to obtain, after five years of experience. A slight error in its cutting and handling, and this dish could cause the death of the diners.
The poisonous parts vary depending on the type of fugu (Japanese for the pufferfish dish). For some species the skin and many parts of the meat are poisonous too!
In general, the most poisonous parts are the ovaries, liver and intestines, but an untrained chef can contaminate the entire interior during preparation. The symptoms of poisoning begin with a burning sensation in the mouth, then dizziness, numbness, body itching, rapid heart rate, low blood pressure, vomiting and, finally, muscle paralysis.
The toxin acts on the diaphragm muscle, paralyzing breathing, which leads to death. And in case you were wondering: No, there is no antidote, nor does the poison disappear after boiling or cooking the fish. You can only resort to supportive treatment when the damage has already been done. Due to its deadly nature, it is illegal to eat this fish in many countries.
What does a puffer fish feed on?
We have already talked about what happens if you try to eat pufferfish, but what does this fish feed on? Well, it feeds at night on anything it finds. However, its favorite food is small invertebrates, such as snails, clams, mussels and urchins.
The pufferfish’s four teeth are fused together and are used to break through hard surfaces. So while they can also eat algae, sponges and corals, they need hard objects to wear down their teeth. So foods like shellfish, shrimp and snails are key.
Males build sandcastles
Another interesting fact about these fish is that males are capable of building “sand castles” on the seabed to impress females. Thus, the males dig with their fins and bodies until they build beautiful geometric rings that are true works of art. To do this, the pufferfish works tirelessly for more than a week.
When the female approaches the circle, she is attracted by the spectacular drawing and decides to deposit her eggs in the center of the structure, at which time the male will be able to fertilize them.
In some pufferfish species it is the males who protect their eggs. Their job is to keep them in good condition and protected from predators until they hatch and the babies are born, after about four days. How romantic!
Conservation status of pufferfish
The International Union for Conservation of Nature Endangered lists some pufferfish species are endangered or critically endangered due to overfishing, habitat loss and pollution.
Sometimes people take these fish out of the water and leave them on the beach to die and dry, just to earn a souvenir. Remember that no matter how entertaining these animals look, they are not toys or ornaments.
What if people just want to touch them and then put them back into water? It’s dangerous to us, but also – when we touch them – we scare and stress them. When they inflate, they use up a lot of energy and become exhausted. So please, respect wildlife.
Bottom line: Pufferfish have a cool but deadly defense. When threatened, they swell with air or water and most are covered in sharp spines. They also contain a toxin much stronger and faster-acting than cyanide.
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