Derasa Clam (Tridacna derasa)

Tridacna derasa is also referred to as the Southern Giant Clam or Smooth Giant Clam, and is the second largest of all the Tridacna spp., reaching a size of 24" in the wild. Unlike most other Tridacna spp. that have a large byssal opening, Derasa Clams have a narrow gap on the underside of their thick, smooth shell. They can easily be confused with their close relative Tridacna gigas, especially when they are very small in size. T. derasa can be identified by having six to seven vertical folds in their shell which they can close completely, where T. gigas has only four or five vertical folds, and is unable to completely close their hinged shell.

Tridacna derasa are the hardiest and most adaptable of all the Tridacna spp., and require moderate to intense lighting and good water flow in the home aquarium. Proper water chemistry is very important, and they will thrive when calcium levels of 380- 450 mg/L, alkalinity level of 8-11 dKH, and magnesium level of 1280-1350 ppm are maintained.

Please Note: Colouration can vary from predominantly brown markings to predominantly blue. Photo shown is for reference only.