Zebra Crabs: Coral destroyers or Tank cleaners?

[luckycharm]

I added some crabs to my tank a few days ago to help keep it clean. The red and blue crabs are great. They dont bother anybody...just happily snack on all the algae that my snails were ignoring.
I have 3 zebra crabs and an angry chunk of xenia that was, until yesterday, quite happy. I cant keep the 3 guys away from it. They're acting like a pack of dogs on a steak! Ive been reading posts from other people who have had similar experiences with their zebras...but havent read any resolutions.
Are they doing something good for the xenia? The black and white stripes looked cool in the LFS but now...they just look evil. Are they? Should these evil creatures be removed and left alone in my QT??
I looked on live aquaria...the doctor's prognosis:
Temperament: Peaceful
Reef Compatible: Yes
So what gives? Am i just being an over-protective xenia parent?

 

[kynekke]

The worst mine have done is to knock the Xenia off it's home. Could they be cleaning the rock it's on and subsequently irritating it?

 

[luckycharm]

Thanks for the reply. Thats exactly what i'm wondering. The biggest of the crabs appeared to be cleaning the xenia itself. He was standing in it and it looked like he was poking the coral instead of doing stuff with the rock. Thats why I'm asking...have they been known to 'clean' coral? Does coral need cleaning? Can stuff grow on the coral that crabs or snails can eat off of them?

 

[luckycharm]

So maybe I am just looking at the situation in the wrong way. Maybe these guys are just cleaning the rock and happen to be close to the xenia. They could be irritating it in the process of cleaning the rock.

 

[uberlink]

If you're worried about them, then I would get rid of them. It is not generally good to have anything picking at your corals--regardless of whether the crab's intentions are good. (I'm not even sure crabs can form intentions.) I would throw them in your sump and sleep better. Stick to red and blue legged hermits. (Reds are my favorite...very gentle on corals.) Get these guys out of there.

 

[jerthunter]

My zebra hermits are amazing and I have never seen them hurt any of my coral. Sometimes they crawl over some zoos and disturb them but I have never seen them damage anything. I suppose it is possible that they are hurting your coral, but I really doubt they are attacking the xenia, I would bet they are just climbing around on the rock with the xenia and disturbing it.