Common name: Large Burrowing Sea Cucumber

General information

The Giant Clam, scientifically known as Massinium magnum, is a species of bivalve mollusk that is highly sought after in the reefkeeping hobby for its impressive size and the vibrant colors of its mantle. These clams are known for their symbiotic relationship with photosynthetic algae, which live within their tissues and provide the clams with nutrients through photosynthesis.

Giant Clams are peaceful and non-mobile, spending their lives attached to a substrate. They are filter feeders and also rely on the symbiotic algae, known as zooxanthellae, for nutrition.

Care

Giant Clams require intense lighting to support the photosynthetic needs of their symbiotic algae. They also need stable water conditions with high water quality, including low nitrate and phosphate levels. Calcium and other trace elements should be maintained at natural seawater levels to support shell growth.

These clams prefer to be placed on a stable substrate or attached to live rock where they can securely anchor themselves. They should not be moved frequently as this can stress them and disrupt their feeding.

Reproduction

In the wild, Giant Clams reproduce by spawning, where they release eggs and sperm into the water column. In the aquarium, breeding Giant Clams can be challenging and is typically done by advanced hobbyists or commercial aquaculture facilities.

Symbiosis

The symbiotic relationship between Giant Clams and zooxanthellae is a classic example of mutualism. The clams provide a safe habitat and the compounds necessary for photosynthesis, while the algae supply the clams with oxygen and a significant portion of their nutritional needs.

Habitat

Massinium magnum is found in the warm waters of the Indo-Pacific region. They inhabit shallow reefs and lagoons, often in areas with strong lighting which is essential for their symbiotic algae.