Sign of a really happy clam?

[Aframereef]

My derasa clam started doing that a few weeks ago. Never have seen this before. Looks Great otherwise. He sucks it in and out. Just hanging low today.

 

[Flippers4pups]

Bump

 

[xjiang7]

That would be its foot

 

[Aframereef]

I've had this clam for 4 years and another like it for 4 years and have never seen its foot. I just made some improvements to my tanks water quality.

 

[reef lover]

They do this sometimes...nothing to worry about. Wait till you see him stick it right out and give himself a shove!!