Common name: Southern giant clam

General information

The Derasa Clam, Tridacna derasa, is one of the larger species of giant clams found in the reef aquarium trade. Known for its smooth shell and vibrant coloration, which can range from blues and greens to golds and browns, this clam is a sought-after addition to many reef tanks. It is capable of reaching a significant size, making it a centerpiece in larger aquariums.

Care

Derasa Clams require intense lighting to thrive as they harbor symbiotic algae, zooxanthellae, within their mantle tissue. These algae provide the clams with much of their nutritional needs through photosynthesis. Stable water quality, with adequate calcium and trace elements, is essential for shell growth. They should be placed on stable substrate or rockwork where they can attach themselves firmly.

Reproduction

In the wild, Derasa Clams are broadcast spawners, releasing eggs and sperm into the water column. In the aquarium, breeding is less common, but with proper conditions, it is possible to witness spawning events. The larvae are planktonic before settling and metamorphosing into their adult form.

Symbiosis

The symbiotic relationship between Derasa Clams and their 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 portion of the organic compounds they produce.

Habitat

Tridacna derasa is native to the Indo-Pacific region, typically found in shallow reefs and lagoons. They prefer sandy bottoms or reef slopes where they can receive ample sunlight for their symbiotic algae.