Clam won't stay put!

[ponokareefer]

I have read you can put Crocea's in the sand, if you put a rock/shell large enough for it to grab onto under the sand. My crocea that I just got is in the sand, but attached to a very large rock that starts probably 4 inches under the sand and goes up probably 8 inches above the sand. As Tony pointed out, their foot has to have something to fully attach to, whether that's up in the rock work, or down in the sand with rock underneath the sand.