David Fleetham / Coral goby (Bryaninops loki) resting on on a Giant clam (Tridacna gigas) mantle, Indonesia, Pacific Ocean.

Sergio Hanquet / Giant clam (Tridacna gigas) on coral reef with shoal of fish swimming by in background, Ari Atoll, Maldives, Indian Ocean.

Shane Gross / Shells from Giant clams (Tridacna gigas) left on the seabed after being discarded by fisherman, Tubuai, French Polynesia, Pacific Ocean.

Lewis Jefferies / Giant clam (Tridacna gigas) mantle detail, Red Sea, Egypt.

Alex Mustard / Large giant clam (Tridacna gigas) growing on a coral reef. Saunderek jetty, Raja Ampat, West Papua, Indonesia. Dampier Strait. Ceram Sea. Tropical West Pacific Ocean.

Alex Mustard / Two giant clams (Tridacna gigas) growing on a coral reef. Arborek Island, Raja Ampat, West Papua, Indonesia. Dampier Strait. Ceram Sea. Tropical West Pacific Ocean.

Shane Gross / A Giant clam (Tridacna gigas) surrounded by Lettuce coral (Turbinaria reniformis), Kosrae, Micronesia.

Willem Kolvoort / Giant clam (Tridacna gigas) on sea floor in shallow Passe Dubois lagoon, Aldabra, Indian Ocean

Willem Kolvoort / Giant clam (Tridacna gigas) in the shallow reef, Passe Femme / Femme channel, Aldabra, Indian Ocean

Willem Kolvoort / Giant clam (Tridacna gigas) in the coral reef with hard corals and soft corals, Cosmoledo Island, Seychelles, Indian Ocean

Willem Kolvoort / Giant clam (Tridacna gigas) in coral reef, St. Joseph, Seychelles, Indian Ocean