Any experience with sand sifting crabs???

[erock]

I've never seen these before and was curious if anyone has had experience keeping these crabs in their reef tank.

http://www.saltwaterfish.com/site_11_03/product_info.php?products_id=301&parent_category=4&category_search=63&root_parent_id=4

 

[Ashlar]

I saw those, too, a while back.. I couldn't find much information on them other tan they're lumped in a big group of crustaceans commonly called sand fleas.