Acro Crab - sure can hide
 

Got a nice piece of acro a couple of days ago. Though gave a real good look (scared of Red Bugs) when first got the coral, some how missed the crab until tonight.

Appears the type here, smooth white with black band.

I did the same thing when I picked up an acro not to long ago. Lookeed in store and didn't see anything then saw it moving when mh when out. Then found one in the next acro I got a week after and this one was alot bigger, don't know how I missed it for so long.

It could be that it/they transferred to that acro from another in your tank. I've read of that happening.

Yeah I have at least 4 in my tank. Two of them have moved into different colonies from the ones they came in on. But yes they do hide quite well. The last colony I bought had one that I saw in the store but upon investigation before placing it in the tank I found there were two living in that colony.