Vermatoid snails on clams shell?

[REEFRHEAD]

ok i just got a nice golden 3 inch maxima clam and the shell is covered with these little snails and im just wondering if anyone has had bad experience with them being on the shells bothering the clam? also i noticed the closest snail to my mantle causes the mantle to not open all the way i figure its because of the snails moving and such and not pm so im going to pull the clam out eventually and clean off all the closest snails anyways but im wondering while im at it should i just scrap off every single one i find?

 

[a4twenty]

i have left them on in the past with no problems but if he is having a negative impact on the clam i wouldn't hesitate to scrap it off.