A squamosa clams is what you need to begin with...Squamosa Clams are relatively hardy and less demanding than most other Tridacna species, 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. What type of lighting do you have and what size tank do you have.....here is a pic... of mine...