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Animal profile

Giant Clam

Tridacna gigas

BivalviaShallow, clear tropical reef flats within reach of strong sunlightVulnerable

Field profile

The giant clam is the largest living bivalve, reaching shell lengths above one metre and weights over two hundred kilograms. It lies with its hinge down and its brightly patterned mantle exposed to sunlight. Adults are permanently fixed in place and cannot close fast or fully.

Scope note

This is an editorial profile, not a diagnostic field-identification guide or a substitute for current conservation assessments. Follow the cited sources on each fact for the evidence trail.

Published field notes

2026-02-21

Giant Clam

The giant clam farms algae inside its own mantle

Tridacna gigas gets most of its energy not from filtering plankton but from symbiotic algae cultivated in its exposed mantle tissue. The colourful flesh is a solar array, which is why the animal must live in shallow, sunlit water.

Read with evidence →

Giant Clam | Daily Animal Facts