Pufferfish, also known as blowfish, are a group of saltwater and freshwater fish that are known for their ability to inflate themselves by swallowing water or air. They are found in warm and tropical waters around the world, and are prized in some cultures for their meat, which is considered a delicacy. However, pufferfish also contain a highly toxic substance called tetrodotoxin, which can cause serious illness or death if consumed in large enough quantities. As a result, pufferfish must be prepared by specially trained and licensed chefs who know how to properly clean and prepare the fish to remove the toxic parts.