Crab in acro frag

Sea Wizard · Jan 18, 2009

I have a acro frag that I purchased from my LFS. It's light green with small polyps. Any hoo, it has a small crab that stays in the acro, I have removes it and it returns to the same acro. Is it safe? It is cream green color the same as the acro, it has short small hairs growing out of the legs. It has a body shape similar to an emerald, but ???? Will try to get a pic for ID.

Spiderwoman · Jan 18, 2009

Not sure if he is safe or not, but I had 3 in one new SPS that came from an online vendor. I removed them and they are now living in the refugium. Their claws had a sharp point and I always figured that's not a good sign.

GMaquarium · Jan 18, 2009

Does it have a black bandit band on its face or is it fuzzy?

Hypertek99 · Jan 18, 2009

Could be an acro crab??

Sea Wizard · Jan 18, 2009

No black band, but he's fuzzy. The acro colony in the LFS that the frag was from has died. My wife and I were there yesterday and I noticed it was dead. So far I my frag is doing great. The lights are out now and was looking at the crab with a flashlight and noticed him crawling all over the acro like he was cleaning it. Not picking at the polyps, or even the flesh, but like cleaning algae from it?

AquaWorldPSC · Jan 18, 2009

Here's my role of thumb when it comes to acro crabs:
If it is hairy they are bad (not all but most).
If they are smooth and usually have a black band across the face it is good.

Sea Wizard · Jan 18, 2009

Really looks like an emerald except it's fuzzy all over. Color is not right for an emerald (I have 2). Kinda hard to describe. As far as I know or can tell he never leaves the acro. Haven't noticed any damage on any other corals or inhabitants of the tank.

AquaWorldPSC · Jan 18, 2009

Some hairy ones are good, but i would keep an eye on it for the next few days.

Sea Wizard · Jan 18, 2009

Had the frag for 2 months always there in it. What amazes me is that the LFS's colony has died. Mine has put on growth and is thriving! Could the crab be beneficial to the coral? To describe it a little better the eyes and mouth parts are white, but it does have black tip claws. Have read that black tips are a NONO.

AquaWorldPSC · Jan 18, 2009

If it is not bothering it leave it. The frag will benefit by kinda cleaning it. But will also agitate it.

Russellaqua · Jan 19, 2009

check out this site:
http://www.chucksaddiction.com/hitchcrabs.html
it has pics of all sorts of crabs, including acro crabs. It should help you ID what you have.

Russellaqua · Jan 19, 2009

I forgot to mention that the "good" acro crabs are near the bottom under "The Coral Commensal Crabs" I think this guy Jonesius triunguiculatus might be yours from your description. It's white with maybe a hint of green and it's hairy. Let us know what you find out.