hitchhicker crab

Question
Hello! This morning I found a crab in my tnak. Its brow, going  on green, red eyes and it was hiding under my LR in a litle dug out. 2 weeks ago my gobby died and disapeared, but i associated its death with the cycle of the tank, witch is on its last strech. What is this crab? Is it bad? What should i do? Let it in or remove it? On top of that, I saw a red bristle worm the other day, but most people say there good for the tank, your opinion? I have a 29g, 30pds LR, 2 clows, 2 damsels, a cleaner shrip and a pepermint shrimp, and about 15-20 mixt hermit crabs, are they in danger?
Thanks! Pat

Answer
Hey Pat

Bristleworms are harmless and good scavengers, about 1% of them are the species that actually do harm, so the odds are extremely slim you have one of them

I think your gobys death might have been associated with the cycle, and not the crab. However, i believe your crabs species is a hairy emerald, check google to make sure