Help Id: Acro crab?

[Kapital]

I looked for where to post this but was unable to find an id thread. Moderator if you have a better place for this post please feel free to move it.

I got some colonies in and noticed this guy hiding in the colony. I know some acro crabs are good and some are bad. Is this a friend or foe?

 

[JOKER]

That actually looks like an acro crab but im not certain.