Pyramid snails are tiny little terrors who have the ability to reproduce very quickly and their strength comes in numbers. It doesn't take long for a bunch of these little parasitic snails to completely decimate a clam. There are thousands of different species of Pyramid snails so positive ID is nearly impossible, some of them only attack clams and some attack other snails, I have had both types. It is also thought that some have the ability to paralyze a clam with toxic saliva to make it easier on themselves. They kill the clams by using a trunk like proboscis to penetrate the clams mantle and suck the body fluids out. A pic of an adult Pyramid snail next to a toothbrush for size comparison. What you will need to remove these snails from clams, a toothbrush, rigid pointy object I use a pocket knife, but I have used shish kabob skewers in the past, and a tub of water for rinsing. Some people add certain Wrasses to the display tank to help with removing Pyram snails. The problem is that the snails are nocturnal and the Wrasses are diurnal. But IMHO it couldn't hurt to add the Wrasse just in case he snag's a few of them here and there. These snails will be more active when the lights are out so when you do manual removal it is best to do it one hour after the lights turn off. What you will be looking for is tiny, rice grain sized snails near the opening's of the clam. Mainly the snails will be just under the mantle on the shell. This is also where they usually lay their eggs. IMHO the egg masses are just as or if not more important to remove from the clam than the snails themselves. The eggs will be in clear masses usually as close to the mantle as possible. It is hard to see in this pic but they are the jelly like substance just above my horrible blue arrows. What I do is take the toothbrush and thoroughly scrub the clam and rinse it repeatedly in the process. Although scrubbing removes a lot of the snails you can't get them all by doing so, there will be snails deep in the folds of the clams scutes and that is where the knife or shish kabob skewer comes in handy. I dig them out and if there are scutes that are grown too closely together to get into I break the scutes out to gain access because 9 out of 10 times there will be snails in there. Breaking the scutes doesn't harm the clam and it won't feel a thing. Here is a pic of a snail that the toothbrush didn't get. Last but not least you will need to check the bottom of the clam near the byssal opening. The snails usually congregate there during the day. Clean Pyram snails off of clams is a long process, you will need to clean them every other night for at least a month. Even if you don't see any snails on nights still keep checking them till you are 100 percent sure they are all gone. Another thing that I do is place a Tupperware container under the clam with a little bit of sand in it. Every time I clean the clam I throw away the sand in the container and replace it with new sand. The snails will burrow down into the sand to hide during the day.