Physical Description: The tridacna crocea clam, also commonly referred to as the crocea clam is one of the most vibrant clams in the reefkeeping hobby. Color variations include deep, vibrant hues of blue, green, purple and sometimes yellow or gold. The crocea clam uses a byssal gland, which produces byssal threads, referred to as “the foot” for orientation and movement. It will attach itself to surfaces or dig into the sand bed using the bysall threads that extend through the two valves of the clam. The outer shell is harder and thicker than other clams. There are scutes, scale like growth, near the outermost top of the shell. The common size of this clam is between two and six inches but can be found as large as eight inches. This clam is found in shallow reefs in the oceans of the Indo-Pacific with concentrated findings along the coast of Vietnam. Crocea clams have also been found in the Red Sea.
During the acclimation process crocea clam will sometimes attach itself to the vessel used to transport. If this happens, very gently and patiently scrape the foot until it releases its hold on the object. Place a wide head plug in the acclimation tank to avoid having to remove the clam from anything it may attach to. If the byssal threads are damaged the clam may not live long. Crocea will find a spot in the tank substrate where the light source is unobstructed. It will use the byssal threads to dig itself deep into a sand bed or other substrate so that only the mantle is showing above the sand. The mantle is the fleshy, bright colored part of the clam. The clam will then open wide, stretching the mantle toward the tank’s light source.
This is not aggressive livestock. It will not sting or otherwise irritate other tank inhabitants. However, some species of fish have been known to nip or chew at the mantle of the clam.
Aquarium Conditions: Ammonia and nitrite levels should be near zero. A spike in nitrite or ammonia is not always critical as this is hearty livestock; however, regular cleaning is always a good idea. Ideal tank temperature should remain in the range of 76 to 82 degrees Fahrenheit with salinity at 1.024 to 1.026. Low measureable amounts of nitrates are acceptable for this clam. Maintain ideal pH 8.2-8.3, alkalinity at 8-9DKH. Strong lighting, such as metal halides or LED’s, is a must for sustaining life and optimal growth. Water flow can be moderate to strong.
Crocea clam has a symbiotic relationship with zooxanthellae in its mantle and does not require additional feeding; however, it is not unreasonable to feed the clam phytoplankton. Calcium and strontium dosing is necessary for shell growth. Calcium levels should range between 350 mg/L-500mg/L
Breeding: Most clams are farm raised or wild caught. Success with aquarist breeding in a home tank is extremely limited. Farm raised clams are more common now as a result of the popularity with hobbyists. Vivid and unique color combinations are being propagated at the farm level. Also, the crocea clam is the smallest of the tridacna clams; so many hobbyists can easily add a 2-3 inch clam to their aquarium with successful growth and long term reward. –Melissa Ramirez.