Spot-fin porcupinefish (Diodon hystrix)
The spot-fin porcupinefish is a member of the family Diodontidae. It is a medium-sized fish, grows up to 91 cm. The scales are modified into spines. In case of danger, the porcupinefish can inflate itself by swallowing water to deter the potential predator with its larger volume and it can raise its spines. It is found in all the tropical and subtropical waters of the world.