Species · GBIF taxon 4372619
Giant Clam
Tridacna gigasAlso known as Gigas Giant Clam, True Giant Clam
Giant clams are the largest living bivalve molluscs, anchoring themselves to shallow coral reefs where they can grow to over a meter in length. Their massive, fluted shells house a brilliant, fleshy mantle that glows with iridescent blues, greens, and golds due to symbiotic algae living within their tissues. These gentle giants rely on sunlight to nourish their algae, which in turn provide the clam with the majority of its food.
MarineReef-DwellingSymbiotic
Licensed referenceCharles J. Sharp / CC BY-SA 4.0 · cc-by-sa
- diet
- Photosynthetic sugars from symbiotic algae and filter-fed plankton
- family
- Cardiidae
- threats
- Overharvesting for food and the aquarium trade, habitat degradation, and ocean warming
- life Span
- Up to 100 years or more
CR
Safe to observe at a normal distance.
Critically endangered due to decades of intensive harvesting for their meat and decorative shells, compounded by reef bleaching.
Never touch, step on, or attempt to feed the clam; admire its colors from a respectful swimming distance.- Maintain Distance: Avoid touching or hovering directly over the clam, as sudden shadows cause them to snap shut.
- Watch the Mantle: Observe the shimmering iridescent spots, called iridophores, which direct sunlight to their internal algae.
- Do Not Anchor: Ensure boats do not drop anchors nearby, as physical impacts can easily shatter their shells.