What's Destoying My Live Rock?

[kmf507]

I've had a 55g set up for approximately one month. I have started to notice holes burrowed/eaten into my live rock. Upon further inspection, I have found that several of the existing rock cavities have nearly doubled in size.

Anyone have any idea on the culprit type?

[d4a2n0k]

Sounds like a Mantis Shrimp. Do you hear any clicking sounds? Almost sounds like a marble tapping against the glass. Usually more noticeable at night.

Very smart and interesting creatures but almost never suitable for a reef tank. They are very sensitive to movement and will dive into a rock if you walk up to the tank. They are usually watching you without you even knowing. Just be careful for the time being with your hands in the tank until you rule out that it is not a Mantis. They can and will smash your hand and will split you open. They literally smash their way through the rock so just picture what they can do to flesh. Some say that certain species can hit with the force of a .22 caliber bullet.

I had one in my tank for over a year before I even spotted him and kept it for 3 years and never lost a thing. They can and almost always go after snails, crabs and slow swimming fish but if you have a lot of live rock with plenty of pods, you might be able to support it without losing anything like I did.

http://www.wetwebmedia.com/marine/inverts/arthropoda/stomatopods/mantisshrimp.htm

There is also a Mantis Shrimp forum on Reef Central.
http://www.reefcentral.com/forums/forumdisplay.php?s=&forumid=37

[tangman99]

I've had a mantis for 4 years now and I've never seen him. Two big clues give him away though. The clicking noise at night and the pile of snail shells that my wife and I refer to as the killing fields.

[Ereefic]

Could be a rock boring urchin as well.

[kmf507]

Thanks for the replies. I've never heard of a rock boring urchin, but it sounds like an expensive pest (if you have to replace LR until the urchin is gone). I've listened for sounds, and so far have not heard anything I would attribute to a mantis, but it could be there.

I did notice that a small "Meixcan Crab" that the LFS sold for .99 seemed to be digging a hole later last night. Has anyone encountered this?

[RobinsonFam1]

no he was prolly just cleaning a hole.
i had an urchin like that one time, chewed througheverything including an overflow!