How To Care For Reef Tank Clams
Essential Tips for Clam Care
Clams are stunning and beneficial additions to reef aquariums, offering both vibrant coloration and natural filtration. These photosynthetic bivalves can become true centerpieces in your tank, but only if their specific needs are met. Unlike hardy cleanup crew members, clams are sensitive invertebrates that require strong lighting, pristine water quality, and a stable, mature reef system. Before adding one to your tank, it’s important to understand their habitat preferences, water parameters, and long-term care requirements.
General Habitat & Tank Requirements:
Clams are best suited for mature reef aquariums with stable water chemistry and low nutrient levels. They thrive in clean, well-lit environments with sufficient calcium and alkalinity to support their shell growth.
- Tank Size: Minimum 30 gallons for smaller species like Tridacna crocea. Larger species like Tridacna maxima, Tridacna derasa, and Tridacna gigas need 75-100+ gallons due to their potential size and lighting needs.
- Aquascape: Provide stable rock structures for clams to attach to. Avoid placing them on sharp or unstable rockwork. Some clam species like Tridacna derasa prefer to be placed on the sandbed.
- Substrate: Clams can be placed on sand or rock, depending on the species. Maximas and croceas prefer rock, while derasas and squamosas do well on sand.
- Lighting: High PAR lighting (200+ PAR) from metal halide, T5, or high-output LEDs is essential. Clams rely on symbiotic zooxanthellae algae in their tissues to photosynthesize.
Water Conditions:
- Specific Gravity (Salinity): 1.024-1.026
- Temperature: 75-78 Degrees F
- pH: 8.1-8.4
- Alkalinity: 8-9dKH
- Calcium: 380-450ppm
- Magnesium: 1300-1450ppm
- Nitrate (NO3): 10-30ppm
- Phosphate: 0.01-0.1ppm
- Nitrite (NO2): Undetectable
- Ammonia (NH3): Undetectable
Diet and Feeding
Most clams get the majority of their energy from light via photosynthesis, but younger and smaller clams (less than 2") benefit from additional feeding.
Supplemental Feeding: Feed live phytoplankton or a high-quality powdered plankton blend.
Feeding Tips: Turn off flow temporarily when feeding phytoplankton to allow clams time to filter feed.
Behavior and Compatibility
Clams are largely sessile, but can move occasionally. They are peaceful, adding biodiversity and color to the reef tank. With the right placement and conditions, they’ll remain stationary and contribute to overall tank stability. It's important to never move a clam once it's found it's happy spot as this will almost always cause damage to its byssal threads, which can be fatal.
Reef Safe: Clams are fully reef-safe and even beneficial for nutrient export.
Tankmates: Avoid fish that may nip at mantles like certain angelfish, butterflies, and puffers. Wrasses and tangs are generally safe.
Behavior: Clams respond to changes in light and movement by retracting their mantles. This is normal but frequent closing may indicate stress or a predator.
Health and Maintenance
Routine tank maintenance and parameter monitoring are vital to clam health. Shell growth and mantle extension are key indicators of wellbeing.
- Perform regular water changes and employ effective filtration to maintain water quality.
- Test calcium, alkalinity, magnesium, nitrate, phosphate, and salinity regularly.
- Watch for signs of distress: gaping shells, poor mantle extension, bleaching, or pyramid snails (clam predators).
Common Pests & Problems
Even in well-maintained reef tanks, clams can occasionally fall victim to pests or environmental issues. Early detection and proper identification are key to protecting your clams.
- Pyramid Snails: Tiny, nocturnal parasites that feed on clam tissue, often found near the base or under the shell. Inspect regularly and remove by hand or with tweezers if found.
- Fish Nipping: Some angelfish, butterflyfish, and puffers may nip at clam mantles, causing stress or death over time. Watch for repeated mantle retraction during the day.
- Flatworms: Certain predatory flatworms can target clams. A dip may be necessary in severe cases, but should be a last resort and done with caution.
- Clam Gaping: A widely open shell with a gaping inlet and little mantle extension is often a sign of stress, poor water quality, or disease.
- Lighting Shock: Clams acclimated to low light may bleach or close up when suddenly exposed to high PAR.
Adam has been reef keeping since 2010 and got his start on the Bulk Reef Supply Customer Service team. He believes the best tanks are built around what you enjoy, not what’s trending. Adam is especially interested in simplifying the hobby, exploring the latest gear, and helping others focus on long-term success over chasing perfection.
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