Giant clams have a hard external calcium carbonate shell with soft tissues within. Between the two shell halves lies the mantle, a soft tissue layer displaying vibrant colours—purple, green, or yellow. The mantle gets its vibrancy from a symbiotic algae called zooxanthellae that get shelter there, while the clam benefits from nutrients produced by the algae through photosynthesis.

The nutrient source of giant clams is not only from algae found in their tissues. Giant clams are also filter feeders, feasting on dissolved matter and microorganisms by pumping water into their mantle cavity through a siphon and filtering it through ciliated tracts on their gills.

These highly efficient filter feeders help keep their ecosystems healthy by removing excess nutrients from the water. Because giant clams stay in one place throughout their lives, they are vulnerable to pollution and unsustainable fishing. Fluted Giant Clams are listed as Conservation Dependent on the IUCN Red List of Threatened Species and rely on continued protection to prevent them from becoming endangered.