a big enough anenome in a small enough tank in a poor situation (bad acclimation, params, etc), leading to the anenomes death, can release toxins into the water and even crash the tank.
quick question on the clams were they all closed tight and did you notice any of them moved from the original placement and were any of them opened when placed in the tank?
Mike
Dude...sounds like we are hounding you, but some of us know the gut-wrenching feeling when this happens. Everyone's only trying to help, but really...we all want to know what exactly happened here so we can avoid this same situation. Put up the params & some pics tonight if you can.