Acro Crab?

Hey everyone.

I recently added a new acro piece that's about size of a softball.

A crab came inside the acro that's about an 1" from one end of the leg to the other. The body alone is probably about 1/2" or so. AT first I believed this to be an Acro Crab, which supposedly is harmless. I researched pictures of acro crabs and it looks like they're usually white with a black stripe running in the front around the mouth. The one that I have is very similar with the black stripe but it's more brownish/peach color than white. Has anyone seen these kinds of acro crabs?

The reason why I ask is because my softies including mushroom leather, one specific type of zoas, and colt coral has closed up recently. (on a sidenote, the softies are on the other side of the SPS. I made sure they're separated.) I'm beginning to wonder if the crab is to blame.

The crab does not leave the acro, at least the times I've seen it. I turned on the light in the middle of the night and saw that it was still in the acro. However, I can't say for sure that it stays there since I'm looking at the tank about 10-20 minutes at a time, about two to three times a day.

I still have chance to remove the guy since I know where it is. I wanted to see if you guys have seen this type of acro crab an if you think it is likely that the crab is causing the damage.

Thanks.

By the way...

The acro has been in the tank for about 2 weeks and the polyps look healthier day by day. It doesn't appear that the crab is doing any damage to the acro itself.

Hi. Thanks for the reply. I was so worried that now I'm checking your response on my blackberry at the aieport. Not sure this will post correctly but let me try.

Here are some specs.

Yes I also have 29 which is newer but this is an older larger tank.

The tank is 150g with 40g sump and 10g fuge.

1500gph return pump and 2 koralia 4.

Turboflotor 1500 skimmer.

200 lbs plus minus 10 liverock.

Tank is about 2 yrs old

150w x 3 mh

1 male blonde naso

1 male bicolor anthia

Various mushrooms leather zoa lps sps

100 plus red legged hermit

8 turbo snail.

2 sandsifting star

Ammon 0

Nitrite 0

Nitrate below 10ppm

Calcium 400 plus

Alk 10

Temp 78

Ph 8.3

Hope this helps. That was tough typing. I have gotten a better glimpse of the crab and am more convinced that its harmless acro crab. The question is whether or not these things go out of their way and hurt the softies? Thank you.

Thanks Grins. What's WWM?