iD please

[Red Sea reefer]

Hello every one so couple days ago I went to my LFS and I found what in the pic below , so any one know what is this and is it a good idea to add him to reef tank ??

Thanks in advance

 

[Shawn O]

looks like a decorator crab to me.

 

[Sugar Magnolia]

Yes, decorator crab.

 

[lifeoffaith]

Add with caution. All crabs are opportunistic feeders and will eat fish if they get the chance. Some will eat other stuff (corals, snails, etc).