Is this crab reef safe?

[Stanton]

All I could find was xanthid crab and mithrax. This is a borrowed pic, but the same crab in my sump.

 

[DgenR8]

In my book, very few crabs are reef safe. Porcelain crabs make the safe list, because they are filter feeders, and have no actual claws.
What makes a crab bad for your tank is it's claws. Some crabs are built for algae picking, such as the Mithrax, or Sally Lightfoot, and have smooth claws. Crabs that are built for ripping flesh have serrated claws.
It's difficult to tell from that pic, but I'd bet he's got some flesh ripping claws.

 

[Stanton]

The claws have the flat white tips like my emerald. I found him last week and I'm having a bubble algae problem that my one emerald can't keep up with. So I was wanting to move him back up to help out.

 

[ReeferAl]

As Dr Ron Shimek has said, with the exception of filter feeding crabs, all crabs are omnivorous. Some may be relatively less risky in a reef tank than others, but all have the potential of harming corals and other invertebrates. I'm no crab expert, but that looks as much like a mithrax crab as any I've seen. How hard was your crab to catch? If it wasn't too hard you could give it a try and keep an eye on it. If it was very hard to catch then, if it were me, I wouldn't take a chance.
Allen

 

[reeftanker04]

<a href=showthread.php?s=&postid=9730192#post9730192 target=_blank>Originally posted</a> by ReeferAl
As Dr Ron Shimek has said, with the exception of filter feeding crabs, all crabs are omnivorous. Some may be relatively less risky in a reef tank than others, but all have the potential of harming corals and other invertebrates. I'm no crab expert, but that looks as much like a mithrax crab as any I've seen. How hard was your crab to catch? If it wasn't too hard you could give it a try and keep an eye on it. If it was very hard to catch then, if it were me, I wouldn't take a chance.
Allen

Yeah I agree, that crab looks like he could be a pain in the butt. Not to mention he's big enough to knock stuff in your tank out of place. I had an emerald crab that just loved to knock my coral onto the sandbed, needless to say the little bugger is now at my LFS.