Clam dying -- any advice?

[Dag]

The mantle receded and it emitted mucus. It's not gaping. It was in the tank for about 2 months and apparently healthy. It's a maxima. I have another maxima that is doing fine. Is there anything that can be done to save this?

If not, any suggestions as to possible cause and how to avoid in the future?

 

[BonsaiNut]

Mucus means injury. Something is probably eating it. Look for a fish, snail, or worm. Move the clam to the other side of the tank and place it (temporarily) on a plate or other flat surface. See if the mucus goes away and the mantle starts to extend again.

 

[OrionN]

Any picture?
The mantle is it all receded or just part of it?
Minh

 

[Dag]

A few weeks ago, a part receded and it seemed fine, then yesterday all of it receded, attended by mucus release. I think it's dead already.

Thanks.