Species Profile Sections: Info, Discussions & Photos
Info  Quick Care, Species Info, Aquarium Care & Photos
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Description
Derasa Clam
(Tridacna derasa)
Quick Care FactsCare Level: Moderate
Temperament: Peaceful
Maximum Size: 24"
Diet: Herbivore
Aquarium Level: Substrate
Minimum Tank Size: 75 gallons
Reef Compatible: Yes
Water Conditions: 72-78° F, dKH 8-12, sg 1.020-1.025, pH 8.1-8.4
Supplements: Calcium, Trace elements
Coloration: Yellow, Tan, Brown, Blue, Green
Origin: Indo-Pacific, Great Barrier Reef
Family: Tridacnidae
Species: Tridacna Clams
Species Information
The Derasa Clam is also commonly referred to in the aquarium trade as the Southern Giant Clam or Smooth Giant Clam. The latter of these names refers to the relative lack of ribbing and scales on the shell, which sets this species apart from many other Tridacna Clams. The smoothness of its thick shell, and the 6-7 vertical folds helps to differentiate its species from T. gigas, its larger relative which is not as smooth and has 4-5 folds; however, in an aquarium environment scutes may develop.
Deresa Clams mantles are a mixture of orange, yellow, blue, and black and white colors, and are usually a wavy striped or spotted pattern, usually with vivid blues and greens. Derasa Clams have a narrow byssal opening and the incurrent siphon has tentacles. This species is one of the largest of the "giant" clams, and grows rapidly, reaching a maximum size of approximately 20 inches.
Under the proper conditions, smaller Derasa Clams can double or triple their size in less than a year. Because of their strong growth and relative ease of care with the correct conditions, most Derasa Clams in the aquarium trade are usually aqua cultured.
Aquarium Care
The Derasa Clam is the most widely available and hardy of the Tridacna clams. It does require bright intense lighting supplied by either intense power compact fluorescent or metal halide lamps to live, grow, and keep its bright colors. The type of lamp will depend on the depth of the tank and the position of the clam, with metal halide being required for deeper aquariums.
A daylight fluorescent tube such as a 10,000K or 20,000K is also highly recommended. Since the Derasa Clam generates much of its food through photosynthesis, proper lighting for this species is crucial so that it survive and to promote healthy growth. This species of clam also grows to a rather large 20" in size and grows quickly under the right conditions, so placement within the aquarium should be well thought out.
Along with the correct lighting, the Derasa Clam will also require medium water flow, so that it may filter feed on small phytoplankton and other micro-foods within the currents. The Deresa Clam requires calcium levels of 400-480 mg/L, and an alkalinity of 7 to 12 degrees, along with proper levels of strontium and iodine.
Feeding & Nutrition
Deresa Clams rely heavily on the photosynthesis of the zooxanthellae cells growing in its mantle for its primary source of sustenance. For this reason bright intense lighting is required for this species to survive and thrive in an aquarium environment.
However, all clams also require micro foods designed for filter feeders, especially when small, offering such as phytoplankton and other micro-foods or marine snow provide an excellent source of additional nutrition.
Additional Photos