Giant Clam

Giant Clam, huge clam occurring widely in shallow waters on coral reefs throughout the tropical Indian and Pacific Oceans. The giant clam is the largest bivalve in the world, reaching to over 1.35 m (4 ft 5 in) across. It is easily recognized by its large size and thick wavy opening, through which the brightly coloured edges of the mantle bulge. Despite this, they are very well camouflaged as they live sunken between corals.

Giant clams filter food particles out of the water, but they also have another special way of obtaining food. Living within the brightly coloured mantle lobes are thousands of microscopic algae that live in a symbiotic relationship with the clam. The algae produce food by photosynthesis that is then used by the clam; in this way, the algal symbionts are capable of producing the clam's entire daily nutritional needs.

Scientific classification: The giant clam belongs to the class Bivalvia of the phylum Mollusca. There are seven species of giant clam worldwide, with Tridacna gigas being the largest of these.