Maxima Clam

Maxima Clam: The Colorful Jewel of the Reef

The Maxima Clam (Tridacna maxima), also commonly known as the Small Giant Clam, is perhaps the most popular and visually stunning of all the giant clam species kept in the marine aquarium hobby. Renowned for its incredibly vibrant and intricate mantle patterns, which often display electric blues, greens, yellows, and purples, it serves as a magnificent centerpiece in any reef tank.

Unlike the truly massive T.gigas, the Maxima Clam is one of the smaller species, reaching an average size of 6 to 8 inches (15−20 cm) in captivity, though some may exceed 12 inches. It is native to the shallow, brightly lit reef flats of the Indo-Pacific, which dictates its primary requirement: extremely intense lighting.

Success with the Maxima Clam is dependent on maintaining impeccable water quality and providing the high light intensity necessary for the symbiotic algae (zooxanthellae) in its mantle to thrive. This clam is considered Intermediate to Advanced in care level.

Diet & Compatibility:

• Diet: The Maxima Clam is a Photosynthetic Filter Feeder. It receives the vast majority (up to 90%) of its nutrition from the symbiotic zooxanthellae algae housed in its mantle tissues. It also filter feeds on phytoplankton, bacterioplankton, and particulate organic matter from the water column.
• Feeding in Captivity: Clams larger than 3−4 inches usually rely solely on light and dissolved organics in a well-stocked tank. Smaller clams (less than 2 inches) benefit greatly from supplemental feeding of phytoplankton or zooplankton several times per week to support their rapid growth and survival.
• Lighting: Extremely High Intensity is required. Lighting should be comparable to the requirements for high-light SPS corals (e.g., Acropora). Place the clam high in the rockwork to maximize light exposure. Lower light will lead to bleaching, starvation, and eventual death.
• Placement & Attachment: The Maxima Clam must be placed on a hard, stable substrate like live rock or a clam tile. It will use its byssal threads (or "foot") to securely attach itself. Never forcefully pull an attached clam from the rock as this will fatally injure its foot. Once attached, it should not be moved.
• Water Flow: Requires moderate, turbulent, and indirect water flow to bring nutrients and remove waste. Avoid strong, direct blasts of flow, as this can stress the mantle tissue.
• Reef Compatibility: It is Reef Safe and peaceful. Monitor for predators, especially parasitic Pyramid Snails (tiny, white, rice-shaped snails found near the shell edge), and large, predatory crabs.
• Water Quality: Requires immaculate and highly stable parameters to build its shell:
  • Calcium: 400−450 ppm
  • Alkalinity: 8−12 dKH
  • Magnesium: 1280−1350 ppm

Quick Facts

• Scientific Name: Tridacna maxima
• Primary Common Name: Maxima Clam
• Other Common Names: Small Giant Clam
• Origin: Indo-Pacific (Widespread)
• Max Size: 6−12 inches (15−30 cm)
• Temperament: Peaceful
• Diet: Photosynthetic Filter Feeder (Zooxanthellae + Phytoplankton)
• Minimum Tank Size: 40 Gallons (stability-wise, 100+ is better)
• Reef Compatibility: Yes
• Lighting Requirement: High to Very High (Intense)
• Care Level: Intermediate to Advanced