I bought 5 astrea snails yesterday and slowly aclimated them. When I put them in my tank they were all stuck together in a clump and stayed that way until I went to be 4 hours later. When I got up this AM I couldn't find any of them and they are still MIA this evening. I have 4 hermit crabs, 1 cereith snail and a chromis plus all the stuff from my LR, LS. Should I worry? 
