Pufferfish refers to fish of various genera in the order Scleractinia, order Puffinidae and family Puffinidae. They are highly poisonous.

A few species enter rivers anadromous to spawn during the reproductive season. They mainly live in the middle or bottom layer of water.

It is a benthic fish with river and sea migratory habits. Puffer fish have a mixed diet, mainly feeding on shellfish, crustaceans, and juvenile fish.

Pufferfish are widely distributed around the world and there are more than 200 species of pufferfish.

Tetrodotoxin is a highly toxic marine bioactive substance, making it an important toxicogenic factor in seafood poisoning incidents.

Poisonings caused by tetrodotoxin, mainly due to accidental ingestion of toxic tetrodotoxin fish, occur frequently in some countries in Southeast Asia.

Scholars have conducted a series of studies on the source of tetrodotoxin. It was found that tetrodotoxin is not only present in tetrodotoxin, but also widely distributed in other animals.

The toxin is also secreted on the body surface in amphibians such as Newts, salamanders, tree frogs, and short-headed toads.

At the same time, a variety of bacteria have been found to produce TTX, and more research has been conducted on the chemical properties and pharmacological and toxicological effects of tetrodotoxin.

As the research progresses, the safety of consuming wild tetrodotoxin will be further enhanced, and tetrodotoxin will have a broad application prospect in the medical field. 

The most researched tetrodotoxin origin theory is Oriental puffer fish, and it is generally believed that the possibility of tetrodotoxin produced by puffer fish migrating down to the sea is

1. Oriental pufferfish produce TTX by themselves in the seawater environment after descending into the sea.

2. Some organisms in the seawater contain TTX, which is absorbed and stored in the body after being swallowed by the puffer fish.

3. TTX is found in the metabolites of many organisms in the ocean.

The whole body of puffer fish except muscles are all toxins, and the distribution of toxicity has the following five characteristics.

1. The amount of toxin contained in puffer fish varies in different parts of the body. Generally speaking, the ovaries contain the most, the liver the second, and the blood, eyes, gills, and skin contain a little.

And the muscle does not contain TTX, but after death, the toxin in the internal organs of the fish can penetrate the muscle, at this time the muscle also contains a small amount of TTX.

2. The toxicity of different kinds of puffer fish varies. For example, fish of the genus Oriental puffer in the family Pufferidae generally contain high toxicity, while fish of the family Prickly puffer and the family Box puffer generally do not contain toxicity.

3. Geographical differences of toxicity. The toxicity of the same kind of puffer fish, living in different seas, has significant differences after being caught.

4. Seasonal differences in toxicity. The toxicity of puffer fish varies with the season, especially during the spawning period (December to June), which is very toxic.

5. Generally speaking, the toxicity of wild puffer fish is stronger than that of farmed puffer fish.

All puffer fish (Tetraodontidae) contain TTX neurotoxin. Although the potency of the neurotoxin varies among different species of puffer fish.

Regardless of the species, 16 mg is enough to kill a 70 kg human being if eaten, or less than 2 mg if injected. Tetrodotoxin is the most toxic fish in the Guinness Book of Records.

Tetrodotoxin is an amino-perhydro quinazoline-type compound, one of the most toxic neurotoxins found in nature, and was once considered the most toxic non-protein toxin in nature.

The toxin has a local irritant effect on the intestine and acts rapidly on nerve endings and nerve centers after absorption, blocking sodium channels on the excitatory membrane with high selectivity and affinity, impeding nerve conduction and thus causing death by nerve paralysis.

The symptoms of pufferfish poisoning appear depending on the physical condition of the person and the amount of TTX ingested.

In general, the poisoned person first suffers from paralysis of the lips and tongue, followed by paralysis of the motor nerves, then dilated peripheral blood vessels, a drop in blood pressure, respiratory distress, and finally, with the slow loss of consciousness, the respiratory center is completely paralyzed until death.

Death usually occurs within 4~6h after the onset of the disease, and those who do not die after 8h can usually recover, mainly because of the rapid detoxification and excretion of TTX in the body.

There is no special medicine for puffer fish poisoning, and the onset of puffer fish poisoning is fast and the mortality rate is high, so the treatment should be based on early emetic, gastric lavage, and excretion.