Keeping a clam from Publix (supermarket) alive

My wife decided to make some linguini with clam sauce one day using canned clams and about a dozen live clams. I took one of the live clams and threw it in a rubbermaid container I have with live rock that is currently curing. The clam has been in there for about 3 weeks now and today I just tossed it in my display tank. Within the 1st 10 mins, it buried itself in the sand and opened up a little bit with it's "thing" hanging out.. i guess it's filtering for food. The clam survived however many days in the Publix cold display case, then 2 days in our fridge and now it seems happy being back in water. My question is, will there be any harm done to my reef with a clam from the seafood section of Publix living in my reef tank? It seems to do a good job with stirring up the sand.