To ward of predators this fish species "puffs" up its belly with water. The belly is covered with prickles and can look very intimidating. The Lagocephalus lunaris is able to do this because it lacks ribs and has very elastic skin!
Learn about another fish that "Puffs" up, The Japanese Pufferfish!
As observed in the photo above, the Green Rough-Backed Puffer Fish received its common name because there are little prickles on its back that extend from the nape to caudal peduncle.