Yeah, I agree. Once their byssal threads are torn or damaged, u can kiss goodbye to ya clammies.
QUOTE(iantoh @ Apr 23 2007, 04:22 PM)

hi there bro Lorenzo,
you can use a pair of scissors to cut apart the two clam's byssal threads that have attached to each other. These are the filaments at the base of the clam's shell- be careful not to injure the clam's actual tissue that is wedged under the base of the shell, just cut the threads in the middle of the air between the two clams will do. and you can leave the sliced filaments as they are, however they dangle and return the clams to your tank. i wouldn't recommend trimming all the threads till both are pretty as this will more often than not, infringe on the tissue area or unduely stress the clam. Also, you can do this out of water without much problem.
This will not do either of the clams any damage, and thereafter, its just a matter of repositioning the clams as you would like them to be positioned. I have done this many times before, after reading of its safety, so don't worry ya.
one thing to note though, a definite no-no is pulling the clams apart by force, as the byssal threads are attached to the soft tissue base of the clam, so pulling them apart injures the tissue base. cutting is alot better and entirely safe. additionally, crocea clams are naturally rock-boring clams, as opposed to some of the other clam species that occur more frequently on sandy substrates, so better to place your croceas on a hard footing in the future, so that their byssal threads can find something firm to attach to.
cheers, and all the best,
ian