ID This Crab

Found this in my tank just recently. My tank is a year old have not added any live rock in awhile. How did this get in here and what type of crab is it?

 

I can say without a doubt it is not reef safe, whatever type of crab it end up being. Get it out before it eats stuff you don't want it to.

See the claws? Those are sharp, and used for killing critters.

 

How do you know, I know certain ones that look like it are only algea eaters.

 

Well, emerald and red mithrax crabs do not have their eyes on extended stalks like your crab does. Extended eye stalks are more suited to see moving food (fish, snails etc) than the short stalks that mithrax crabs have. I was a biology student in college, so I understand form vs function.

Also, the pointy claws give it away as being bad. The only 2 exceptions to pointy claws being bad are porcelain crabs and acro crabs, and even some think acro crabs eat coral flesh from time to time. Mithrax crabs have blunt ends to their claws.

Melev does not have a pic of a crab like yours but if you look at a mithrax crab, you will note the claws and eyes are very different than your crab's.

http://www.melevsreef.com/id/emerald_crab.jpg

 

Believe it or not, it looks like a Red Orange crab. Seriously, we purchased a crab from our Local Fish Store that looked like yours. When we asked what the scientific name was the store manager showed us the shipping manifest and it was listed as a Red Orange crab. He said that it was reef safe. We did not notice any problems with it. However, he dissapeared after a couple of days.

 

Well I will monitor it. I must of been in their awhile cause I have just noticed it. Corals are doing fine though along with fish so I am not sure.

 

I found this crab ID page.
Crabs -- Gallery -- GARFISHINDO Tropical

click on the orange crab, and look at that. I certainly would not put that in my tank, unless I had a puffer and trigger FO tank.

 

It does not have that big of claws and that back 2 legs are blue

 

I would just assume it's not reef safe until you have a positive ID on it. There are far more unsafe crabs than safe crabs AFAIK and once they get in the tank some crabs are very difficult to get out if they find a home inside a rock somewhere you can't get to easily.

My 2c.

 

I am with screwtape. Catch it if you can, while you can. It may not be easy, or even possible to do soon.