Porcupinefish

Porcupinefish are fish of the family Diodontidae (order Tetraodontiformes).

Public domain picture from U.S. National Oceanic and Atmospheric Administration [full size image]

They have the ability to blow themselves up by swallowing water or air when threatened. They are covered by long spines that stick out sharply when the fish is inflated.

The porcupinefish is closely related to the pufferfish, which does not have spines.

One more thing. What kind of porcupinefish is it, do we know? Btw, it is very cool that you are doing this.