Ok so I went and picked up a derasa clam today from my LFS, I acclimated it for about an hour and a half then put it in the tank without exposing it to the air so I didn't have to burp it. I let it sit in the tank for about an hour and then turned the lights on and it opened up about all the way after about 15 min but then I got to looking and I didn't see my fighting conch anywhere so I checked all over the tank till I found it wedged behind my rock wall. He has gotten stuck before but when I pulled him out this time his foot was hard and he smelled horrible (the whole room reeks now) and I knew he had died. So I took him out and got rid of it and I don't think it was in there like that for very long cause I had not noticed the smell until just then and none of my cleaning crew had made its way of to it yet to eat, but I'm still kinda worried about the tank. I checked the water and my ammonia was at 0, my nitrates were at about 3, and nitrites 0. I went ahead and added some stability to the tank just to be on the safe side but now my clam is about half way closed up and I'm a little worried. Would it be just because it stressed out from all the moving in the tank, the light changes, and all or would it be because of something in the water? I really don't want to lose him cause clams are one of my favorite animals and also he wasn't cheap haha. Thanks for any help and advice.