The family Tridacnidae contains a number of clams that are common in the aquarium trade. Collectively, they are commonly called “Tridacna Clams” by hobbyists. These animals are beautiful, interesting, and highly variable, with no two clams looking alike. Their colorful mantles contain photosynthetic zooxanthellae, similar to corals.
Although very beautiful, clams are not for everyone. However, if you are already a successful reef hobbyist with an established, stable system and high water quality, you probably already have the skills to keep a clam in your aquarium.
Clams should be placed in an area of the aquarium where they can receive appropriate water movement and lighting. Ideally, water movement should be more or less random, surging flow-enough to keep things moving, yet not so strong as to make the clam’s mantle fold over on itself, or force the clam to withdraw its mantle on a continuous basis. In our experience, it’s best to place clams on a hard substrate, upon which they can attach tough fibers, known as the byssus, to secure themselves in place.
Since the majority of the clam species kept in the aquarium come from relatively shallow areas of the reef, they are accustomed to intense light, which is what they should receive in the aquarium. High light intensity is very important. It’s very difficult to over-light clams.
If provided with sufficient lighting intensity, no supplemental feeding of is required. The zooxanthella provide the bulk of the nutrition that clams require, with dissolved nutrients in the aquarium water, such as nitrate from fish waste, providing the rest. Tridacna clams will require stable environmental conditions and excellent water quality.
Clams have few natural predators. However, in the aquarium, the excessive incidental picking activities of fishes like Angelfishes, Butterflyfishes, Tangs, Triggerfishes, and even Gobies and Blennies can irritate clams to the point where they no longer extend their mantles. In addition, there are certain snails, such as Pyramidellidae, which which sometimes plague clams. Fortunately, there are several regularly available wrasses that prey on these snails, such as Halichoeres melanurus, Halichoeres argus, and Halichoeres chloropterus.