Loud Clicking noise coming out of the tank

[ScubaSteve]

Originally Posted by Midway

yeah, maybe that explains two of my cleaner shrimps went missing some time ago.

Uh, yup... that might explain it.

I have the same thing in my tank and I've found that many things actually do it. I thought it was my pistol but when I found him dead in the sump. I've noticed my strawberry top snail do this thing where he twists and pulls himself into the glass really quick and makes a cracking sound. He's been incapacitated for the past week and I still hear it. Haven't seen evidence of another pistol or a mantis... so I leave it to one of the mysteries of the tank.. sorta like how a hawaiian rock boring urchin showed up in my tank without having put anything in my tank for over 6 months and the only thing that went in there in 6 months before that was a piece of dead rock that had been sitting dry for over a year. Weird...

[Pinchy]

Originally Posted by globaldesigns

I have those sounds also... Come and goes. Usually lots of clicks, then nothing for awhile (weeks or months) then it starts up again for awhile, usually in the evenings, when the lights are out.

Based on this comment it is definitely a mantis shrimp. Impossible to catch, i had to tear my tank apart to get mine out. This was the sole reason i bought marco rock for my new 72 bow and used the rest of the old live rock in the sump..