Snail attacked?

[Lauramichelle]

Just noticed an empty snail shell in my tank. All I know I have are blue leg crabs snails and coral. It almost looks like something "burned" it's way in. Any ideas?

 

[Lauramichelle]

It may also be a crab shell. Some of my crabs have white shells

 

[mr_X]

Look for a mucous around the victims. I had a snail predator before called oenone fulgida who would secrete a mucous on slow moving inverts like snails, then burrow a hole in the shell and eat them.
It looks like a bristle worm but has noticeable eyes and instead of bristles, it has rows of tiny legs. It's more yellow than a common bristle however.
Here's some pics....

They generally come out at night.

 

[Lauramichelle]

Hi X. No, I haven't seen anything like that. No mucus and no worms like that at night. Thank you