Mysterious Clicking

[Brit’s Fish]

Wondering what could be clicking in my nano reef? I have a pistol shrimp in another tank & this clicking is not as loud as he usually is. Also, the clicking isn’t always at the same tempo(?)... sometimes it’s one click and another a few seconds later, sometimes 3 quick clicks, etc.
I started this tank with CaribSea LifeRock and some pieces of live rock from another one of my own systems. There are two pieces that I have added from the LFS since then because they had coral on them. What are the chances I have a mantis shrimp without ever seeing it?
There are no caves or piles in this tank like in the one where I have a pistol shrimp.

 

[brandon429]

Cerith snail clicking against glass

For three months I could not find the infuriating e10m click

 

[Brit’s Fish]

Cerith snail clicking against glass

For three months I could not find the infuriating e10m clicking

I really hope it’s something like that! I would love to have a mantis shrimp someday but in a tank of its own.

 

[Samsquanch]

I was prepared to answer pistol shrimp lol. Maybe you got a little one as a hitchhiker on the live rock. It could be a little mantis shrimp, that'd be pretty cool

 

[Steve Erekson]

A mantis is really loud. I can hear my 2.5" wennerae from across the house. If you have one you'd probably know.

 

[Samsquanch]

A mantis is really loud. I can hear my 2.5" wennerae from across the house. If you have one you'd probably know.

Same with my pistol shrimp, my tank is in my basement and my girl and I can hear him clicking from the basement to the other end of the house. I can in fact hear him when im in bed at night lol

 

[Brit’s Fish]

Oh yeah. I have a 2.5” pistol shrimp and that boy is LOUD. I have never heard a mantis shrimp but if they’re as loud as a pistol shrimp, then I’m fairly confident it’s something else. Thank you for all the helpful replies!