Derasa Clam - Tridacna derasa - Medium (ORA)

Clams are wonderful additions to any reef aquaria but do have some requirements that make them more difficult than other inverts to keep. Some research is recommended before purchasing one to find out what species will work the best in your reef aquarium.

Derasa Clams (Tridacna derasa) can grow quite large in the home aquarium. They are typically found with yellow to gold striped mantle colorations outlined in blue or purple. Mantle patterns and colors will vary between individual specimens. Unlike most other species of clams, the Derasa Clam has a mostly smooth shell without prominent scutes. They generally have six or seven vertical folds but can have up to twelve. The shell itself is whitish and fan-shaped when small, becoming slightly more elongated as the clam grows. These clams are usually fairly thin at the top when closed and only slightly inflated towards the bottom.

Derasa's are found on a variety of surfaces. They can grow within colonies of corals (especially Acropora corals) or on sandy flats, rubble piles or rock faces. They are usually found in fairly shallow waters but some have been found much deeper in areas with very clear water.

The "byssal opening" where the foot and byssal threads are extended from on the bottom of the clam is very small on Derasa Clams. Young clams are only lightly attached and this attachment is lost as the clam grows. Some Derasa Clams have even been found with no byssal opening at all. The opening is more slot-like in shape rather than the elliptical or circular opening found on other clams. The top edge of this clam is symmetrical and the clam can close up very tightly.

Derasa's are one of the hardiest Tridacna species. They require strong lighting and ideal water quality and should be placed under high direct light (Metal Halide, VHO, or Power Compact). Smaller clams rely heavily on planktonic foods filtered from the water for their nutrition. They should be fed regularly with various types of planktonic foods like phytoplankton, zooplankton, oyster eggs, rotifers and similar items. Avoid keeping with potential predators or tankmates that may nip at the clam's mantle like some wrasses, angelfish, crabs, and others.

For more information on these and other clams, visit the Giant Clams Species Profile on That Fish Blog by our staff marine biologists.

The clam pictured above is representative only - the coloration of the clam you receive may vary. Please contact the Livestock department for information on availability of specific colorations.

ORA clams are propagated by Oceans, Reefs & Aquariums, the largest marine ornamental fish hatchery in the world. They continuously develop new frags, inverts and fish and many are available in very limited quantities. We are proud to offer ORA's clams as part of our collection.