Invisible predator-popping sounds

[XeniaMania]

I'm trying to see if it's a pistol shrimp or possibly mantis. It's been in my tank for 2 yrs approx. It's getting annoying because my sailfin tang has a rip in the lower fin now and I believe this "shrimp" is the culprit of some of my past deceased fish. It's definitely a snapping sound and I believe I know which rock it's coming from, unfortunately, I have hot pink shrooms growing on it, so leaving the rock out over night or a few days may not be a solution unless I decided to dislodge the shrooms. I have a fireshrimp and cleaner in the tank as well, so they might get caught by a shrimp trap if I purchase it? Anyone have this snapping/popping sound and caught what causes it? Thanks.

 

[DJ88©]

[moved]

 

[Mishap]

If it's more of a click or pop it sounds like a pistol shrimp. Mantis is usually a smack or thud.

 

[XeniaMania]

Wouldn't a smack against rock sound like a click tho? hmmmm Like taking a crab leg that you eat and smack it against a rock would produce the same noise I hear.