Ultra Grade Maxima Clam (Tridacna maxima)

The Ultra Grade Maxima Clam (Tridacna maxima) is the jewel of a reef tank. "Ultra grade" marks the most vivid, intricately patterned mantles the species produces, electric blues and turquoise laid out in rippling lines that glow under reef lighting. Park it on the rockwork under strong light and it becomes the centerpiece every guest asks about. Browse the rest of our corals and reef livestock while you plan its spot.

Please note: each clam is a hand-picked individual, so the exact mantle pattern you receive may vary slightly from the photo. You are welcome to come see it in store.

Care Guide

Giant clams feed themselves two ways: zooxanthellae in the mantle turn light into food, and the clam filter-feeds plankton from the water column. Give it the light and clean, stable chemistry it needs and it does the rest.

• Minimum tank size: 30 gallons with true reef-grade lighting.
• Lighting: Intense. Maximas sit high on the rocks in nature, so aim for strong LED or T5 output.
• Flow: Low to moderate and indirect. The mantle should ripple, not fold over.
• Water: 75 to 80°F, specific gravity 1.024 to 1.026, calcium 400 to 450 ppm, alkalinity 8 to 11 dKH, magnesium near 1300 ppm.
• Feeding: Mostly photosynthetic. Clams under about 3 inches especially benefit from regular live phytoplankton.
• Placement: Set it on rock or rubble where it can grip with its byssal foot. Once it attaches, do not pry it loose; move the rock instead if you must.

Specifications

Compatibility

Maxima clams are completely peaceful and sit beautifully among corals, they have no sting at all. Keep them with reef-safe fish and inverts: clownfish, gobies, blennies, chromis, tangs, cleaner shrimp, and snails are all fine. Skip known clam-nippers like large angelfish, butterflyfish, and triggerfish, and inspect the shell occasionally for tiny pyramid snails, removing any you find. Slow, stable, reef-quality water is the real requirement.

Recommended Foods & Supplies

• Bulldawg Reef Juice Clam Blend, a live phytoplankton mix made for clams and filter feeders.
• Quantum Easy E Calcium and Quantum Easy Z Alkalinity to keep shell-building chemistry steady.
• A reliable kit from our water testing collection and a quality mix from salt mixes.
• Browse the rest of our corals and reef livestock.

FAQ

What does "ultra grade" mean?
Clams are graded by mantle color and pattern. Ultra grade is the top tier: saturated blues and intricate patterning across the whole mantle rather than patches of brown.

How much light does it really need?
A lot. Maximas live near the surface on the reef. A proper reef LED or T5 fixture running at coral-growing intensity is the baseline; under dim light a clam slowly starves.

Do I need to feed it?
Larger clams mostly feed themselves through light and by filtering the water. Smaller clams, under about 3 inches, appreciate regular phytoplankton like the Reef Juice Clam Blend.

Where should I place it?
On rock or a rubble bed under your strongest light, with gentle flow. It will attach with byssal threads, and once attached it should not be pulled free.