Derasa Clam

Geographical Origin and Habitat: Native to the southern Indo-Pacific. Found on outer reef slopes and shallow sandy lagoon areas.

Taxonomy: Classified within the Cardiidae family (subfamily Tridacninae). Features a heavy shell with smooth ribs and an expandable mantle.

Social Behavior: Sessile and peaceful. Anchors itself to substrate when young, resting on the sandbed as it grows larger.

Coloration and Sexual Dimorphism: Mantle displays intricate brown, gold, orange, and blue-green wavy patterns. Simultaneous hermaphrodites.

Tank Setup: Place on a sandy substrate. Provide moderate, indirect water flow; direct strong jets will stress the clam.

Diet and Feeding: Photosynthetic. Relies on zooxanthellae for food under strong reef lighting (PAR 150-300). Young clams may accept fine phytoplankton.

Water Quality: Demands stable calcium (380-450 ppm) and alkalinity (8-12 dKH). Keep salinity stable at 1.024-1.026.

Compatibility and Tankmates: 100% reef-safe. Avoid keeping with nipping fish such as angel fish, butterfly fish, or certain wrasses.

Aquarium Breeding: Hermaphroditic broadcast spawning. Spawning in tanks can occur but larvae rarely survive without specialized setups.

Risks and Diseases: Vulnerable to pyramidellid snails, copper toxicity, and tissue recession if calcium levels drop.