WILLIAM OSBORN / Sea holly on beach {Eryngium maritimus} Mid Glamorgan, Wales, UK

Constantinos Petrinos / Broadclub cuttlefish {Sepia latimanus} deimatic display, defence, gives illusion of

Constantinos Petrinos / Steephead parrotfish sleeping in mucous 'bag' {Scarus gibbus} Red Sea, Egypt

Jeff Rotman / Crown Toby pufferfish inflated at night {Canthigaster coronata} Red Sea, Egypt

Jeff Rotman / Porcupine fish close-up of spines {Diodon hystrix} Red Sea

Constantinos Petrinos / Radiant sea urchins {Astropyga radiata} stick close together in defence on sea floor Sulawesi Indonesia, providing shelter / mini habitat for fish and crabs

Jeff Rotman / Lunar fusilier fish schooling {Caesio lunaris} Red Sea

Jeff Rotman / Glassy sweepers schooling {Parapriacanthus guentheri} Red Sea

Jeff Rotman / Glassy sweepers schooling {Parapriacanthus guentheri} Red Sea

Jeff Rotman / Glassy sweepers schooling {Parapriacanthus guentheri} Red Sea

Jeff Rotman / Masked pufferfish inflated at night {Arothron diadematus} Red Sea, Egypt

Jeff Rotman / Yellowspotted pufferfish inflated (Chilomycterus spilostylus) Red Sea

Juergen Freund / Leopard sea cucumber extrudes toxic tentacles in self defence

Fred Bavendam / Cavalla (Caranx sp) juveniles using a Blue Jelly (Catostylus mosaicus) as a shelter from predators, Andaman Sea, Burma

Florian Graner / Moray eel (Muraena helena) in defensive posture, on sea-floor, Norway.

Nature Production / Diver above squid ink floating in the sea, Wakayama, Japan, March

David Hall / Spider crab {Macropodia sp} decorated with stinging hydroids for defense. Red Sea

GEORGETTE DOUWMA / Broadclub cuttlefish male guarding female {Sepia latimanus} Andaman sea,

GEORGETTE DOUWMA / Stonefish buried on sea floor {Synanceja verrucosa} Red Sea Eygpt