A blowfish is a poisonous fish that can quickly puff itself up to escape other fish that might eat it. Unlike some fish, blowfish are not fast swimmers and need other ways to defend themselves. Their excellent eyesight and ability to puff themselves up for a burst of speed allows them to better escape predators. This fish is not just one species though, nor do all the species belong in one genus. Over 120 species of fish in at least 20 genera have adopted the common name of blowfish, pufferish, or balloonfish.
The appearance of this kind of fish can differ greatly from one species to another. They can be many colors, including white, gray, and blue. Their stomach, which is the body part capable of puffing up, is often a different color than the rest of the body. Some blowfish have stripes, splotches, or dots that decorate their skin. It is common for the fish to have spikes protruding from its body as additional protection against predators.
Another natural defense of the blowfish is its toxicity. Most species have poisonous internal organs, and some even have poisonous skin. Even if the fish is killed and consumed by a predator, these natural defenses can cause serious illness or death. Its predators are not just other fish, but humans as well.
Blowfish are eaten as a delicacy in some parts of the world, such as Thailand and Japan. While the skin and internal organs are not safe to eat, the meat can usually be cooked and consumed without worrying about poison. Eating blowfish prepared by a cook that does not regularly deal with this type of fish is still dangerous though. Unskilled cooks have accidentally killed their guests by not removing the proper organs and skin. Depending on what species and organ was consumed, however, it is possible for humans to survive blowfish poison.
These fish can be found in natural bodies of salt- or freshwater, and in aquariums. When kept in captivity, they are normally not poisonous, as the toxins they use are found in natural bodies of water. While keeping the fish as pets is usually an option, they may require more upkeep than more common aquarium fish, such as goldfish. In general, they need a covered tank to prevent them from jumping out and must be supplied with shellfish to keep their teeth from growing too long. The type of tank required depends on the species of fish, as they can grow anywhere from 1 (2.5 cm) inch to more than 2 (0.6 m) feet long.