strange happenings

[DMBillies]

I noticed about 3 weeks ago that my small group of blue zoas with orange mouths looked like the skirts were chewed up and they were shrunk up a bit. I assumed it was nudibranches. I had just added another set of zoas (which look fine) and thought maybe I got some hitchhikers (I dipped the other zoas but didn't quarantine because my 10 gallon is occupied). I figured I'd let it go a few days and have a look in the tank at night to see if I could find anything. However, since I noticed the problem, they have done nothing but recover and look like they are about back to where they were when it happened. In those 3 weeks I also noticed that some of my long-polyp green pipe organs look like their little arms have been chewed off and some of my xenia and green star polyps look like their missing fingers. Same as the zoas, the damage seems to have happened overnight and since I noticed the damage, they have done nothing but get healthier looking. The damaged corals are spread across my entire tank, with similar types between them that seem to be entirely undamaged. My SPS, LPS, and leathers are all looking great. Does anyone have any ideas? Has anyone heard of emerald crabs doing such damage (my only recent addition...he was in there for at least 3-4 weeks before any damage occured)? I haven't added any live rock or fish in about 6 months and I don't think it's likely any of my fish got an appetite for corals (clowns, gramma, pj cardinal, chromis, goby, bi-color blenny).

 

[fishdoc11]

An occasional Emerald will pick at corals(sps in my experience, particularly stylophoras) and could be the problem. Bi colors are notorious nippers of sps and can acquire a taste for some LPS and clams. Definitely sounds like you have something munching through the tank but hard to tell who or what until you catch them in the act.
Chris

 

[DMBillies]

I've seen the blenny occasionally nip at some of my sps and particularly a monti cap, but only the day or two after adding them to the tank and then never a problem after that. I've never seen him munching anything else, but I guess it is possible. Perhaps when I move my tanks I'll qt the emerald crab and see if the problem goes away.

 

[EvilMel]

What about star fish? Got any serpents or brittles?

My green serpent star eats xenia. It looks like the tops of it are chewed off each morning. I'm not bothered by this because I don't like xenia and it's the only thing he seems to have taken a liking to, but I have definitely seen this guy do the things like you are talking about.