Pufferfishes

Scientific name : Tetraodontidae

Mainly tropical fish family, belonging to the Tetraodontiformes order, includes about 100 different species. They all are charachterized by bulbous shape, pointed snout, small mouth, teeth fused in a beak wth 4 plaques, 2 above and 2 below, with a median suture (the word Tetraodontidae means "4 teeth"). The skin is soft and scaleless. Pufferfish swim waving the dorsal and anal fins, using the tail as a rudder, and the pectoral fins to help maneuvre.
The common name indicates the possibility of those fishes to inflate themselves, swallowing water, to become larger and spherical, more difficult to handle for a predator.
They live in all the reef environments, feeding on algae or invertebrates. Sometimes they look for invertebrates blowing water on the sand.
Almost all pufferfishes are toxic. In fact they produce and accumulate the dangerous tetrodotoxin (one of the most powerful animal poisons - see also the blue ring octopus) in the gonads and liver. Some also exudates a toxic mucus. In many cases a clear warning colour communicates to the predators their toxic nature.
They lay sticky benthic eggs. In some species the male guards the nest.
They can be confused with the related families of box fishes and purcupine fishes. The rounded shape, without corners, is a good diagnostic toward the former, the absence of spines toward the latter.
Even if dangerous, because toxic, in Japan some species are considered a gourmet dish. They have to be prepared carefully immediately after the death, to avoid that the toxin, contained int the liver and gonads, contaminate the flesh. Also long heat exposure denaturate the toxin. The ability of the cook is in a careful dosage of the poison, to achieve a slightly narcotic effect. Any mistakes are often fatal.
Is is clear from a recent study that the power of inflating has dramatic effects on blood circulation (due to the increased internal pressure) and on digestion (due to the stomach change in volume), and it is therefore the last resource, that a puffer fish can use for a limited number of times (7 to 12), to avoid death. For this reason we invite all the divers to not provoke puffer fish "inflation": this means a useless stress for the fish, that significantly reduces its life span.

	Description	Author	Place	Size
	Pufferfish inflating during a Lizardfish's attack	MATTEO GUARDINI	Indonesia, Lembeh strait	759 kB