Crab ID please

[niewie]

Hi,

I discovered last night, that there are two crabs in my tank that I did not put there. Must have come with one of the live rocks... They almost seem like a pair in the way they walk around together and sometimes crawl over one another.
They only come out at night with only moonlight on, and are VERY shy.

Can you please indentify the crab in the attached photo, as tell me if they are reef safe?

Thanks

Martin

 

[Jstdv8]

i was always told the rule of thumb for crabs is "shrap claws =bad"
im no expert, just passing on this info.

 

[goose777]

looks like and emerald crab to me

 

[VacavilleFC3S]

definitely not an emerald crab, it's most likely rock crabs which will kill your other livestock

 

[Pulp Fishin]

http://www.chucksaddiction.com/hitchcrabs.html

This page should help Id your crab.
I would guess its probbly a Xanthidea crabs. You will want them out they kill.

 

[Guygettnby]

i also say that is a mithrax crab (AKA Emerald crab) alittle hard to tell from pictures but that would be my guess. would need a close up of the claws to be sure.

but 1 way to make sure of this is to look at the tips of the claws. if they are sharp and pointed the crab is a meat eater for sure. if they are kind of blunt and flat they are omnivores. but this does not mean they will not eat meat aswell if given the chance. if a sick or dying fish swims by or is laying on the sand they will eat it and the same goes for corals. all crabs are opertunist eaters and should be watched, this includes all hermit crabs aswell.

 

[AJSTITAN14]

It looks like a Xanthid to me. You don't want it.