Pufferfish toxin

The Pufferfish is considered the second deadliest vertebrate in the world, after the Golden Poison Frog. The common image we have of this creature is that it inflates when threatened. I have kept these fish in an aquarium, and in my experience they rarely puff out in captivity.

What makes the Pufferfish, also called the Fugu so popular is the lethal toxin in its liver, skin and the ovaries, and the fact that the Japanese treat it as a delicacy. Pretty ironic I guess? By the way it is extremely expensive and prepared only by trained, licensed chefs who, like all humans, occasionally make mistakes.

Image: blogs.bootsnall.com

Almost all pufferfish contain tetrodotoxin, a substance that makes them foul tasting and often lethal to fish. To humans, tetrodotoxin is deadly, up to 1,200 times more poisonous than cyanide. The toxin paralyzes the muscles, including the muscles in our diaphragm, which is essential for breathing. The victim eventually dies of asphyxiation. There is enough toxin in one pufferfish to kill 30 adult humans, and there is no known antidote. Tetrodotoxin has been isolated from widely differing animal species, including western newts of the genus Taricha (where it was formerly termed "tarichatoxin"), pufferfish, toads of the genus Atelopus, several species of blue-ringed octopuses of the genusHapalochlaena (where it was called "maculotoxin"), several sea stars, certain angelfish, a polyclad flatworm, several species of Chaetognatha (arrow worms), several nemerteans (ribbonworms) and several species of xanthid crabs.

Tetrodotoxin molecule

Image: gastroville.com

Negative aspects aside, Puffer Fish makes cute companion.

Of course, don't go around scaring puffer fish because a puffer fish could only perform a limited number of inflation in its life.

Image: animals.nationalgeographic.com

When a Pufferfish is threatened, it will pump itself up by taking 35 gulps or so in the course of 14 seconds. Each gulp draws in a big load of water thanks to some peculiar anatomic changes in the muscles and bones. The entire fish balloons as it continuously takes water into its stomach.

The stomach expands to nearly a hundred times its original volume, and the fish's spine, already slightly curved, bends into an upside-down U shape, and all other internal organs become squeezed between the fish's backbone and its rapidly expanding stomach. Meanwhile, the fish's skin is pushed out, obscuring most of the puffer's features-http://divingintaganga.blogspot.com/2010/09/how-and-why-pufferfish-inflate.html

Image: Sally J. Bensusen. American Museum of Natural History.

Sometimes they have difficulties expelling water from their stomach, and hence they actually risk dying every time they inflate. I guess we should record a default video showing one individual inflating itself on a public website to prevent curious divers/swimmers/fishers going around harming more Pufferfish. Pufferfish belong to family Tetraodontidae is a family of primarily marine and estuarine fish of the order Tetraodontiformes. The family includes many familiar species, which are variously called pufferfish, puffers, balloonfish, blowfish, bubblefish, globefish, swellfish, toadfish, toadies,honey toads, sugar toads, and sea squab. They are morphologically similar to the closely related porcupinefish, which have large external spines (unlike the thinner, hidden spines of Tetraodontidae, which are only visible when the fish has puffed up). The scientific name refers to the four large teeth, fused into an upper and lower plate, which are used for crushing the shells of crustaceans and mollusks, their natural prey.

With all of this, many people still consider Fugo to be a delicacy , especially in Japan.


info:
http://www.aquaticcommunity.com/predatory/pufferfish.php
http://en.wikipedia.org/wiki/Fugu
http://divingintaganga.blogspot.com/2010/09/how-and-why-pufferfish-inflate.html