Sue Daly / Feather duster fan worm (Sabella spallanzanii) with tentacles moving in the current, Sark, British Channel Islands, UK, August.

Nick Upton / Velvet swimming crab (Necora puber) in a rock pool, hiding among Coralweed (Corallina officinalis), Cornwall, UK, March.

Nick Upton / Strawberry anemone (Actinia fragracea) in a rock pool alongside Coralweed (Corallina officinalis), Cornwall, UK, March.

Nick Upton / Common shore crab (Carcinus maenas) hiding among Coralweed (Corallina officinalis) in a rock pool, Cornwall, UK, March.

Pascal Kobeh / Field of Peacock feather dusters / Spiral tube-worms (Sabella spallanzanii), Canary Islands

Nick Upton / Coralweed (Corallina officinalis) from Atlantic Ocean. Cornwall, England, UK. September.

Franco Banfi / Coral Rabbitfish (Siganus corallinus) portrait, Tubbataha Reef Natural Park, UNESCO World Heritage Site, Sulu Sea, Cagayancillo, Palawan, Philippines

Georgette Douwma / Coral rabbitfish (Siganus corallinus) Mabul, Malaysia.

Georgette Douwma / Coral rabbitfish (Siganus corallinus) two swimming side by side, Mabul, Malaysia.

Philippe Clement / Common Coral Weed / Coralweed (Corallina officinalis) washed ashore on beach, Normandy, France. September

Pascal Kobeh / Spiral tube-worm (Sabella spallanzanii), Gozo Island, Malta. Mediterranean Sea.

RHONDA KLEVANSKY / Coral crassula (Crassula corallina) Richtersveld National Park and World Heritage Site, Northern Cape, South Africa, August.