Scientists believe it to be the second-most poisonous vertebrate in the world after the golden arrow poison frog of South America. A poison called tetrodotoxin is present in pufferfish liver and sometimes skin. Pufferfish are also known as bubblefish, blowfish, balloonfish and toadfish. They have thin spines that are visible only when they are completely puffed up. The fish inflates its yellow underbelly by filling it with water when attached, making it too big for the predator to bite or swallow.
When the puffer is threatened, the stomach expands into the peritoneal space and the stomach unfolds to fill gaps beneath the head, dorsal, anal fin and caudal peduncle. The fish balloons and the spines that lie on the surface of its skin stick out, making it a highly unattractive meal!
Although puffers have evolved to suck in water, if lifted out they can sometimes suck in air. They sometimes have difficulties expelling this from their stomach, so take extra care when catching them.
Picture Credit : Google