Porcupinefish

On our dives, we often encounter porcupinefish.  Many of them keep their distance as they look at us, before deciding to swim away.  However, this fish wasn't spooked by my presence, and swam around me, letting me view it from a couple of angles.

The porcupinefish (a relative of the balloonfish) has long spines, which are erected only when the fish inflates.  The color of their back varies from shades of olive to brown, and their belly is white.  The body and fins are covered with small dark spots.

This fish was about 18 inches long, and the photos were taken at a depth of about 50 feet.