The puffer fish is named after its ability to inflate itself like a ball in danger or stress. They pump water into a sac-like enlargement of their stomach, causing them to deform into a ball. This change in volume makes it almost impossible for predatory fish to swallow the puffer fish and it can even suffocate them. If this stress reaction is caused willfully by divers, puffer fish can sometimes inadvertently suck in breathing gas from divers, which leads to them being buoyant and floating helplessly on the surface. This usually ends fatally for the animal. They are rarely eaten by predatory fish, but dolphins have been observed to get intoxicated on these animals by chewing lightly on them, which causes the puffer fish to release small doses of the strong neurotoxin tetrodotoxin. This poison is fatal to humans and no antidote is known; ironically, however, in Japan puffer fish is considered a delicacy called fugu. However, people’s curiosity about this questionable delicacy leads to accidents every year.
There are more than 120 species of puffer fish worldwide. Most can be found in tropical and subtropical regions. However, species have already penetrated the Mediterranean through the Suez Canal. They are shy animals that swim slowly but are incredibly agile. As a rule, they avoid divers and snorkelers, but can be easily observed, for example, at cleaning stations or during twilight / night dives. Diving with the cute looking fish is very enjoyable but is unlikely to be seen in their “inflated“ state. They are not dangerous to the diver unless they are touched. The fish are excellent at defending themselves with their sharp teeth. Click here to find the best areas around the world to dive with these cute but defensive fish.