How and why do puffer fish blow up?

Puffer fish, also called blowfish, have a very fitting name! They can go from their normal fish shape to a round ball to get away from predators. The secret trick to blowing up like a balloon is having a stretchy stomach. When puffer fish feel threatened, they fill their stretchy stomachs with lots of water, which turns them into big, round balls that are hard for predators to swallow. This isn’t the only defense that puffer fish have against predators! Many species also have toxins in their body that make them poisonous or taste disgusting, or spines on their skin to make them spiky and hard to eat. Despite all these tricks, some people still enjoy eating puffer fish! The dish is called fugu in Japan and must be prepared by special chefs who know how to remove the toxins and make it safe to eat.