Loud sounds at night!
 

Ive just recently added some moon lights to the tank. So know i can see whats going on at night. So the other night i was checking it out and i was hearing this loud clicking sound. It happens now and then its not constant. My tanks been running for little over month and a half now.. Any idea on what this could be?

Mantis Shrimp!!

... or a fish snapping at the surface, or a shell hitting the glass, or a pistol shrimp, or a heater turning off for the night etc etc etc.

added any new LR lately?

Yes i have added some LR lately. I know the sound of my crabs/snails hitting the glass and it is way louder then that. My heater is not that loud as well.. Say it was a mantis shrimp or pistol shrimp. Would i see them come out at night? Thanks for the help.

any mantis that you'll ever see will be diurnal; very unlikely you'll actually see it at night although my mantis has been up late clicking away before (not often though). pistol shrimp are secretive pretty much all of the time. some pistols will make pretty obvious tunnels in the sand. watch around the tank for broken shells of hermits/crabs/snails (mantis).

Also a Mantis usually sounds like something clicking on glass where a Pistol Shrimp has more of a snapping sound.

Sounds like you have a hidden pest in your tank. If it is a mantis and it is aggressive like my old mantis you could use some bait to try and lure out.

What would lure him out. Shrimp? Mysis shrimp? Would this work for the pistol shrimp as well?

http://www.stomatopod.com/forum/viewtopic.php?t=71

mantids aren't picky. pretty much any meaty marine meat. I would avoid any bivalvemeat if it stays in there for a long time... that stuff degrades faster than others. dunno bout pistols though.

I used clams to lure my mantis out. I purchased the cold water variety from the grocery store and placed it in the open sand area. The mantis would appear instantly to snatch it up.

I don't know if pistol shrimp are that aggressive since I have never owned one. The lure method might not work.