need ID on hitchhiker crab

[papania]

We have a hitcherhiker crab that came in our fijian liverock. It's about an inch across, only comes out at night, and even then is very shy. It's gray or black with white spots/stripes on its legs. It's defininatly not a hermit crab or shell-hosting species.

Will try to get a picture but the critter is fast. Want to know if it's likely to be a pest or okay.

Does anyone have any guesses or can you let us know common species that may fit the description?

 

[romunov]

Most crabs will not be welcome in a reef tank. It's impossible to tell without a picture anything about yours.

 

[romsoccer12]

if u can capture it put it in your sump
a glass bowl going downward with some shrimp may work than you can ID it