© iStock-stephankerkhofs The Pufferfish’s Larger Cousin Not to be confused with its smaller cousin, the pufferfish, you can distinguish porcupinefish by their elongated bodies and large eyes. There are several species of porcupinefish within the Diodontidae family, all of which can inflate their bodies when provoked or threatened. They activate this unique defense mechanism by swallowing water or air to increase their size and cause the sharp spines covering their bodies to stand on end. You can go diving with porcupinefish worldwide on shallow reefs in temperate and tropical waters. Porcupinefish are not only identifiable by their spine-covered bodies, but they are typically brownish-yellow in color and covered in small black spots with a white underbelly. Your best bet on encountering porcupinefish is on a coral or rocky reef or near caves, shipwrecks, or ledges. To discover where you can go diving with porcupinefish, explore the dive site map below.