Description
Maxima Coloured Cultured Clam (Tridacna maxima)
(Also known as the Small Giant Clam or Maxima Giant Clam)
Overview
The Maxima Clam (Tridacna maxima) is one of the most vibrant and sought-after species of giant clam, renowned for its brilliantly coloured mantles that shimmer in shades of blue, green, gold, or purple, often with intricate patterns and iridescent highlights. Cultured specimens are sustainably farmed and more adaptable to aquarium life than wild-collected individuals. Reaching around 20–30 cm (8–12 inches) in length, T. maxima is the second smallest of the Tridacna species but one of the most visually striking and rewarding for reef keepers.
Origin
Native to the Indo-Pacific region, including the Red Sea, Fiji, Tonga, the Philippines, and the Great Barrier Reef. Found in shallow, sunlit reef flats and lagoons, often attached to hard substrates such as coral rock. Cultured varieties are raised in controlled ocean nurseries to promote sustainability and resilience in aquarium conditions.
Lighting
High lighting required. The Maxima Clam hosts symbiotic zooxanthellae in its mantle tissue, which provide most of its nutrition via photosynthesis. Intense, full-spectrum lighting such as LED, T5, or metal halide is essential.
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Place in the upper half of the tank or directly on the substrate under strong lighting.
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PAR levels of 250–400 µmol/m²/s are ideal for colour and growth.
Water Flow
Low to moderate, indirect flow. Water movement should be sufficient to deliver nutrients and oxygen without disturbing the mantle, which should remain fully open and gently undulating. Avoid direct blasts from powerheads.
Feeding
Primarily photosynthetic, but juvenile or smaller clams benefit from supplemental feeding.
Feed 1–2 times per week with:
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Live phytoplankton (essential for clams under 3 inches)
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Marine microalgae blends
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Commercial clam or coral foods (fine particulate)
As the clam matures, it becomes almost entirely self-sufficient via photosynthesis and filter feeding from the water column.
Placement
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Place the clam on solid rockwork or a stable substrate, as it uses a byssal foot to anchor itself.
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Ensure the mantle receives full, unobstructed light.
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Avoid moving the clam frequently; once attached, relocation can damage its foot.
Tank Mates
Reef safe and peaceful, but sensitive to predators. Suitable companions include:
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Reef-safe fish (clownfish, tangs, gobies, wrasses, etc.)
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Clean-up crew (snails, hermits, urchins)
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Other peaceful corals
Avoid:
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Butterflyfish, angelfish (especially large species), puffers, and triggers, which may nip the mantle.
Aggression
Non-aggressive. Does not harm or sting other tank inhabitants but should not be placed too close to corals with long sweeper tentacles.
Experience Level
Intermediate to advanced. Cultured clams are hardy once established but require strong lighting, stable water chemistry, and careful acclimation.
Water Parameters
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Temperature: 25–28°C (77–82°F)
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pH: 8.1–8.4
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Salinity: 1.024–1.026 SG
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Hardness (dKH): 8–12
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Calcium: 400–450 ppm
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Magnesium: 1250–1350 ppm
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Tank Size: Minimum 100 litres (25 gallons) for juveniles; 200+ litres (50+ gallons) for adults
Stable calcium and alkalinity are crucial for shell growth. Protein skimming and regular water changes help maintain clarity and trace element balance.
Reef Compatibility
Fully reef safe. Will not harm corals or invertebrates and thrives in mature, stable reef systems. Its vivid mantle adds stunning visual contrast to reef aquascapes.
