- "I caught a blowfish! And that's not just hot air!"
An information board in the aquarium will provide information about this fish.
"Blowfish are considered a delicacy, famous for their tempting taste despite being highly poisonous. Blowfish are not poisonous at birth, though, which makes young ones relatively safe for consumption. It's only once they have ingested enough microbes from seawater and food that they become poisonous. When they feel threatened, they suck in air and water to blow themselves up like balloons. This makes them too big to eat without predators being forced to chomp down on their poison quills."
In real life
The Japanese Puffer, also known as the Tiger Puffer, is a blowfish found primarily in Japan, in salt water near coral reefs or near shores, mainly. Their diet consists mostly of algae, mollusks, invertebrates, and sometimes crustaceans. They have very strong teeth that may grow too long if the fish doesn't eat abrasive food.
The main defense of the fish is the neurotoxin in its internal organs (mainly the liver, ovaries, intestines, and skin). The toxin is called tetrodotoxin, and is 1200 times more deadly than cyanide. This is created by bacteria within the fish that it obtains by eating food containing the bacteria. Since it needs the bacteria to become lethal, this is a safe method of breeding them, since they are a delicacy in many countries.
Due to the Japanese Puffer's genome being very small, it has become a model organism for identifying genes and other elements in human and other vertebrate genomes.