Giant Clam

The giant clam is the largest living bivalve mollusc on Earth and a magnificent fixture of Komodo's healthy reef ecosystem. These incredible animals can reach shell lengths of over 1.2 metres and weigh more than 200 kilograms, living for over a century in some cases. What makes giant clams truly remarkable is their mantle — the fleshy tissue exposed between the shell halves is covered in an extraordinary array of iridescent blues, greens, purples, and browns, created by symbiotic algae (zooxanthellae) living within the tissue. These algae photosynthesise using sunlight, and the clam has evolved specialised structures in its mantle that act like tiny lenses to distribute light to the algae deep within its tissue. The majority of the clam's nutrition comes from these algae rather than from filter-feeding. In Komodo, giant clams are found on reef flats and slopes where they receive ample sunlight, and their vibrant mantles are a favourite subject for underwater photographers. Each individual has a unique mantle pattern, like a living, shimmering work of abstract art embedded in the reef.