Spider Crab-like creature in my LR

Is this thing harmful? it just stays in my LR... it comes out only when I feed. The picture is as far as it goes out! Please help! I have no idea what in the world it is, it's very strange the hairs on its legs kind of move.. I haven't seen it attack my shrimp, fish, or hermit crabs....

 

here's another picture...

 

Can't tell you by those pics. We would need to see a decent shot of the pincers to determine whether it was safe or not. I would get it out, get some good pics, then go from there,

 

I have one or two of those same mithrax crabs. I caught one and put it in my fuge because everyone seems to think they can harm your reef tank inhabitants. I never saw mine do any harm but I took it out just in case. It looks like this.


This crazy thing would actually use shells ans small rocks to wall itself into a hole in a piece of live rock. It's still in my fuge but I'm sure it is not as happy in there.

 

it moved!

 

I personally think it is a hermit without a shelll. lol...

 

I have one of those in my 10g. It never harms my corals. However.....and this is a big however......they can. So just beware. As long as they can find food in your tank, I think you will be fine. So I wouldn't rip everything out looking to capture it. But if opportunity presents itself, I would snag it.

 

i think thats a bad one Crab Hitch Hikers

 

Have removed 2 of those crabs from my reef in the space of a year, they were about a inch wide...