Physical Description: The Tridacna squamosa clam, also commonly referred to as the scaly clam, fluted clam or giant clam is bivalve. The shell of the squamosa clam is made up of wavy rows of scutes, or scales. The rows of scutes are symmetrical on either side of the clam. This allows the clam to close tightly when needed. The color of the shell is typically tan or grey but new growth is often white. The mantle has linear and/or spotted markings against different color variations such as brown, green, blue, and purple. The rich blue and vivid purples are wildly popular and will almost always have a higher price range. The spotted markings on the edges of the mantle might appear decorative but are the “eyes” of the clam. The eyes will register movement or shadow above the clam and the clam will quickly close to protect itself against predators. The T. squamosa has a byssal organ, which produces byssal threads, referred to as “the foot,” for orientation and movement. It also has a large inhalant siphon. Its function is to bring water into the body. Visible branching tentacles line the siphon and are used for filter feeding. For a home aquarium this clam can be a large livestock addition, with some clams growing as large as twelve inches. In the wild, most T. squamosa clams are found in shallow waters, not usually greater than 50 feet in depth, around the coasts of Australia, Egypt, the Philippines, South Africa, the American Samoas and Thailand.
Aquarium Conditions:During the acclimation process the clam will occasionally 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. Do not forcibly remove the clam from any surface to which it is attached. If the byssal threads are damaged the clam may not live long. It is important to keep the mantle upright. The mantle contains zooxanthellae and requires strong light to produce the food base for the clam. The clam will use its foot to jump and position itself into an optimal position on substrate in the tank.
This is not aggressive livestock. It will not sting or otherwise irritate other tank inhabitants. However, because of the size and calcium required to maintain this clam, it may compete with stony corals or acropora for nutrients. Some species of fish, such as blennies, puffer fish and angel fish, have been known to nip or chew at the mantle of the clam. An anemone on the move may sting or try to eat a squamosa clam. Keep a safe perimeter from the sweeping or stinging tentacles of other tank mates.
The T. squamosa is hardy livestock, so slight spikes in nitrite and ammonia levels aren’t critical. However, regular tank maintenance is required. 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 LEDs, is a must for sustaining life and optimal growth. Water flow should be low to moderate.
The T. squamosa clam has a symbiotic relationship with zooxanthellae in its mantle. The zooxanthellae are photosynthetic, so strong lighting is key for maintaining a healthy clam. Because it is photosynthetic additional feeding is not required, however, the squamosa is a filter feeder that will process phytoplankton or other trace food debris. Calcium is absolutely necessary for shell growth. Calcium levels should range between 350 mg/L-500mg/L. The key to maintaining this clam is strong lighting and regular calcium dosing; a healthy level of magnesium would be 1280-1350 ppm.
Breeding: Most clams are farm raised or collected in the wild. Success with aquarist breeding in a home tank is extremely limited. Farm raised clams are more common now as a result of the popularity of this species. Vivid and unique color combinations are being propagated at the farm level due to high interest.—Melissa Ramirez.