The Pufferfish Really Isn't Happy to See You

Pufferfish inflate to several times their normal size as a defense mechanism used to avoid predators. Most puffers have extremely elastic skin and can rapidly gulp water (or air, if they're out of water) to expand their bodies.

When a pufferfish inflates, it turns into a spiky, unappetizing ball — basically saying, "Hey, you don't want to eat me!"

Pufferfish have beak-like front teeth formed from fused dental plates. These strong teeth are perfect for cracking open hard-shelled prey like crustaceans.

Some Tetraodontidae species' internal organs — like the liver and intestines — are also packed with a deadly neurotoxin called tetrodotoxin. This makes certain pufferfish extremely poisonous. As of now, there's no known antidote.

Within the pufferfish family, you'll find a variety of species and subspecies. Some of the most famous include the fugu — a delicacy in Japan — and the dwarf pufferfish, which is commonly kept in home aquariums.

Each species has its own adaptations, depending on where they live and what they eat. For example, freshwater pufferfish species have evolved to thrive in rivers and lakes, while others live in salt water near coastal regions.

One puffer fish, Tetraodon nigroviridis, is particularly interesting because it can survive in both fresh and saltwater. And let's not forget the giant pufferfish (Tetraodon mbu) which can grow up to 26 inches (67 cm).

Pufferfish are generally solitary creatures. They don't swim in schools like other fish, and they prefer to hang out on their own unless it's breeding season.

During this time, male puffers put on quite a show. Male pufferfish are known for creating intricate geometrical designs in the sand to attract females. These patterns are not only beautiful, but they also help stabilize eggs laid by the females.

They're not particularly friendly creatures; instead, they're curious and cautious by nature. Pufferfish are known to be territorial, especially when it comes to defending their feeding grounds or nesting areas.

Pufferfish are omnivores, which means they eat a mix of plants and animals. In the wild, their favorite snacks include small invertebrates like shrimp, mollusks and crabs. Thanks to those strong, beak-like front teeth, they can crack open tough shells with ease.

Many species of pufferfish also nibble on algae, corals and sponges. And while many puffers stick to these options, one pufferfish species, the fugu, occasionally enjoys a diet of smaller other fish.

In captivity, people often feed them pellets or frozen food to replicate their natural diet as closely as possible.

Pufferfish live in a variety of aquatic environments, from warm tropical seas to coastal regions filled with brackish water. Some species, like the freshwater puffers, thrive in rivers and lakes, while you can find others in coral reefs or sandy ocean floors.

Puffers typically hang out in shallow waters, rarely venturing into the deep sea. This allows them easy access to their favorite foods, like crustaceans and mollusks, which are abundant in these habitats.

The ability to survive in brackish water gives certain species an extra edge in colonizing diverse environments.

After mating, females lay their eggs in carefully prepared nests created by male pufferfish. The males guard these eggs until they hatch, which usually takes about a week, depending on the temperature of the water.

Once hatched, the baby puffers are left to fend for themselves. They grow rapidly in their first few months and, much like their adult counterparts, quickly learn how to inflate as a means of defense.

While pufferfish can live for several years, their life span varies depending on the species. In captivity, with proper care, puffers can live up to 10 years or more.

While many species are not currently endangered, habitat destruction and overfishing pose threats.

In some regions, pufferfish are harvested for the aquarium trade or for consumption, such as the infamous fugu in Japan. The preparation of fugu is a risky business, as its internal organs contain lethal toxins, and only specially trained chefs are allowed to prepare it.

However, added pufferfish populations in controlled environments — such as fish farms — help reduce the strain on wild populations. Conservation efforts are essential in preserving the diverse range of pufferfish species and ensuring their ecosystems remain healthy for generations to come.

We created this article in conjunction with AI technology, then made sure it was edited and fact-checked by a HowStuffWorks editor.