Acclimation: invertebrates cope badly with even small changes in water chemistry, and clams are sensitive to salinity changes. Acclimate it slowly, by floating and then drip, and never rush the process. It must then get used to the light: a clam under 5 cm has a thinner mantle and is more sensitive to very intense lighting. Start it on the bottom, on a small rock or in a dish of coarse substrate, then move it up gradually, as you would a newly added coral.
Setup: moderate to intense lighting suits it, with moderate flow. It arrives unattached and prefers to sit on the sand or in a rock recess, as it attaches less firmly than other Tridacna. Kept well, a small specimen can double or triple in size in less than a year: plan the space. Never pull it off once it has attached: the foot and tissues would be fatally damaged. As a last resort, cut the byssal threads one by one with a razor blade, close to the surface, without touching the tissue.
Tankmates: it is a peaceful animal that harms nothing, but in an aquarium anemones, triggerfish and puffers may attack it, and a wandering anemone may sting it. Inspect it before adding it, and quarantine it if you can, to spot parasitic Pyramidellidae snails: they are white, conical, a few millimetres long, and feed on the clam on its shell and foot until it weakens or dies. Remove them by hand (a toothpick will do), checking day after day; the wrasses Halichoeres melanurus and Halichoeres chrysus eat them.
Health signs and sensitivities: the mantle edge carries hundreds of simple eyes; the clam partly closes when the light dims, a shadow passes or an object moves, which is a normal reflex. A mantle that no longer opens fully for several days, on the other hand, should make you look for parasites. Like all invertebrates, it does not tolerate copper treatments. It builds its shell from calcium carbonate, so it draws on the tank's calcium and alkalinity.
Water: aim for 22 to 25.5 °C, a specific gravity of 1.023 to 1.025, pH 8.1 to 8.4, 380 to 450 mg/L calcium, 1280 to 1350 mg/L magnesium and an alkalinity of 8 to 11 dKH.
