Gary Bell/ Oceanwide / Porcupinefish (Diodon nicthemerus) in defensive posture, Port Phillip Bay, Mornington Peninsula, Victoria, Australia

Juergen Freund / Globefish (Diodon nicthemerus) swimming past a mass of plastic moving in the current, North Sulawesi, Indonesia.

Solvin Zankl / Porcupinefish (Diodontidae) tiny juvenile, found in plankton community, Sargasso Sea, Bermuda.

Alex Mustard / Spotted porcupinefish (Diodon hystrix) swimming in open water above a coral reef, West Bay, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Georgette Douwma / Black-blotched Porcupinefish / Short-spine Porcupinefish (Diodon liturosus) and a Klein's butterflyfish (Chaetodon kleinii) sheltering in barrel sponge. Komodo National Park, Indonesia.

Claudio Contreras / Balloon fish (Diodon holocanthus) with defensive spines, Puerto Morelos National Park, Caribbean Sea, Mexico, January

Jeff Rotman / Black Blotched Porcupinefish (Diodon liturosus) inflated swimming in open ocean. Sipadan Islands, South China Sea.

Flip Nicklin / Long-spine Porcupinefish (Diodon holocanthus) in defense posture, North America

Fred Bavendam / Porcupinefish (Diodon nicthemerus) swallows water to puff itself up and points its spines outward as a defense against predators, South Australia

Juergen Freund / Balloonfish (Diodon holocanthus). Caribbean

Pascal Kobeh / Common porcupinefish (Diodon hystrix) resting at night. Baja California, Mexico.

Gary Bell/ Oceanwide / Sea Star (Coscinasterias muricata) feeding on Porcupinefish (Diodon nicthemerus) carcass, Port Phillip Bay, Mornington Peninsula, Victoria, Australia