Puffer fish

thingiverse

Porcupinefish are a type of fish that belong to the family Diodontidae, also widely known as blowfish and sometimes referred to as balloonfish and globefish. These fish have the remarkable ability to inflate their bodies by swallowing water or air, which enables them to become significantly rounder in shape. This increase in size is quite dramatic, almost doubling their vertical dimensions, thereby limiting the range of potential predators that can attack them to those with much larger mouths. In addition to this defense mechanism, a second line of protection is provided by the sharp spines that radiate outwards when the fish is inflated.