they do fine. its a cherrystone. i work at a seafood resturant (legal seafoods) and asked a chef for 2 (one for my girl's tank)
i literally popped it from a bucket full of ice into 80 degree cup of water. let it spit all of its stored contents out (and proved its alive) then tossed it in aquarium
i put native mussles in tanks before. they just attach themselves to rock and never move, just opening and closing.....
but these clams move around all the time and dig alot too. its really interesting.
my advice, try it. the most you will lose is $1.00
just do a quick freshwaster dip and besides they survive on ice for so long, i doubt you have to worry about parasites...even then if you have alot of $ invested in a reef....just do a quarantine.
I call them 'quahogs' or some sort. Makes the best clam chowder in the east coast Very hard to find here on the west coast.....although there is a store that I know which sells them live.