New Clam - burping (Urgent)

[Playdope]

Not sure what its doing.. but after drip acclimating a new clam (my 1st time trying to keep one)... I added it to the sugarfine substrate. I wiggled it into the substrate to plant it (didn't want it to topple over). Its been opening and closing every couple of seconds (stressed?). But what I notice is a little cloud of sand from it "burping" a few times. What is it doing? Should I not have wiggled it into the substrate??

Thanks!

[BigDaddy]

What type of clam?

Most maximas and croceas prefer to attach to live rock.

[Playdope]

Its either a maxima or croacea... I'm having trouble telling the difference

Should I move it onto some rock. My only concern was that I've never tried to keep a clam under the lighting I have, and if its not enough, I don't want it to fuse to the rock so that I cant get it off without harming it! I don't see a way to get it to attatch to a small rock that could be moved.

Any info?? I do know its a croacea or maxima.. its electric blue/purple.

I have 432 watts of t5 lighting.