Sorry you lost your clam. I too lost several when I first started with clams. Small clams are harder to keep alive than large ones. All the clams I lost were small, the one I have now I purchased at LFS at around 6 inches and is doing well for over a year now. I just acclimate a little longer than fish, like you I did check temp and salinity of LFS water and to compare with DT water. The small ones require daily feeding of zooplankton and phytoplankton as compared to larger specimens, I'm sure you know what I mean. I forget,, what size tank and how l old is it?