Porcupinefishes are completely covered with sharp spines, and when they are disturbed, distend themselves with water into prickly balloons. This discourages the attack and makes it difficult or impossible to swallow them. If they are removed from the water, they inflate with air and make little croaking noises. There are 3 porcupinefish species in Hawai'i.
The porcupinefish has a large head and eyes, which makes its narrow body seem gaunt in contrast. Its entire body is covered with small black dots and spines lie flat against it. They typically rest under a ledge during the day. This is the largest of the porcupinefish. The species name means "porcupine" and the Hawaiian name means "spiny".