Here is a new one. I purchased 2 crocea clams about 2 weeks ago. I acclimated them slowly and introduced them to my tank so that they enjoyed as close to the same light level as from the place I purchased them. They both had small rocks attached to their feet so I proceeded to place them on my live rock in a safe flat spot.
They quickly opened up and enjoyed their surroundings. Over the next day or so they tilted and opened up further. A few days later one of the clams moved around a little and approached the edge of the live rock and started to tilt off it. I gently tried to move the clam; however, it had clamped on to the live rock - so I let it be.
The next day it had fallen off, so I placed it on the sand to see how it responded. It opened up & tilted. The next day it was covered by hermit crabs and had been devoured.
I thought it probably damaged its foot and died.
A few days ago, my other clam moved (it was still up on the live rock) and fell off. I rescued it and put it in the sand & watched it to see if it was being harassed. Nothing. Everything seems to be great for about three days. This evening I see the cleaner shrimp eating the clams foot about 10" away from the clam (the foot is still attached to the small rock I bought it with but obviously not attached to the clam). The clam is on its side yet still open. Thinking that it is dying I am looking for any other obvious injuries. A fish swims by and it closes up just as if I was to pass my hand between it and the light.
I don't have any doubts that this guy is a goner too; however, what in the world would separate a clam from its foot on the sand? Are there any known predators in the bristle worm family? I have seen a few of those. Or maybe my serpent stars (I have got two harlequins)? Any insight would be great.
My wife will be adding some pictures tomorrow.
Also adding that this morning the clam seems to be fine. He has righted himself on the sand and is open with good color. The cleaner shrimp is still working on eating the foot.