Snails attached to clam

[jetson]

I am moving some of my rock work around, and need to move my Deresa in the process. I didn’t realize until I picked it up but there are three snails attached to its base. I don’t want to injure the clam by yanking them off, but not sure that this is safe for the clam for them to be there anyway.
Is it safe for the clam to just pull them off, or is what is the safest way to proceed?

 

[BriDroid]

Mine will grab onto small rocks and shells/snails and hold on to them. I’m guessing that’s what’s going on here.

 

[minus9]

They're just cleaning algae on the shell, no harm in removing them.