clam looks like its taking deep breaths?

[aquajamieb]

I have a derasa clam in my 20 long under 2x65 watt 50/50 pcs. It looks like its taking deep breaths, and blowing sand all over the tank. I have it in the sand, but on top of a small piece of live rock, for it to attach too. Why is it taking these deep "breaths"?

 

[Travis]

It isn't taking deep breaths. It is expelling particles that get caught in its gills. Pretty much the same as when we cough or sneeze.