Scientific Name: Tridacna Gigas
Common Name: Giant Clam, Gigas
Location: Indo-Pacific
Diet: Phytoplankton.
Size: 54 inches (137 cm)
Compatibility: Does well in any tank that doesn’t have Wrasses, Angle Fish, Butterfly Fish or others that may nip at the clams’ delicate mantle.
Suitability: Easy
Minimum Tank Size: N/A
Reef Safe: Reef Safe
This is the largest of the Giant clams. Unfortunately while fairly commonly available in LFS, it is an endangered species and lacks the vivid color of the T. Maximas and T. Croceas. Nonetheless there are some Aqua-Cultured (CITES Agreement regulations prevent the harvest and selling of wild caught specimens in most cases) specimens that are available in several color morphs. Most however are fairly drab in color with some occasional color spotting. Smaller examples under three inches will require spot feeding on a regular basis with phytoplankton as these clams have not yet developed enough mantel size to produce adequate nutrition through photosynthesis. While algae in the clam mantel on larger specimens will generally provide sufficient nutrition they will still benefit from an occasional spot feeding.
These clams are best kept in very large tanks and moderately intense lighting. In Smaller tanks such as 75 gallon tanks VHO’s usually prove adequate. In tanks with depths deeper than 24 inches, they will do best under 150-175 watt 6500K halides. A three inch Juvenile will quickly outgrow a 75 gallon tank sometimes taking just 12 months to do so in an optimally set up tank. Keeping Giant Clams such as this one will tax even the best systems calcium levels. This will often require the reef keeper to “drip” Kalkwasser or use a Calcium Reactor in order to keep up with the demand for these “Calcium Hawgs”. . Additionally the Reefer will have to keep in mind the other inhabitants in the tank as many fish will pick at the mantle causing the clam to close up too much or too often due to the harassment and cuase it to slowly starve. There are several pest that can afflict clams as well. The most notorious of these and most dreaded is Pyramid Snails. These resemble small grains of white rice in size and can often be found in the gap areas where the clams to shell halves come together. All clams should be carefully inspected for these before purchase! These clams will do best when placed at the bottom of the tank in a sand bed 3-6 inches deep.