Good? Bad?

[Y-DesygnGuy]

I found this guy in my tank yesterday, after things have been set up for a month now!

Is it good or bad for my reef tank?
Sorry for the bad picture it will not let me take a good picture of him, he is very shy and bails back into the rocks at the first sign of movement.

 

[billsreef]

Crabs with large heavy claws like that one are typically destructive.

 

[650-IS350]

I don't trust any crab, only reef safe crabs are Porcelin crabs.. ( Filter feeders ) anything else is considered opportunistic bastards.

 

[ACBlinky]

I have a very similar Xanthid crab that hitchhiked into my reef, his name is The Beast, and he lives in my 30g reef along with a mantis, a pair of maroon clowns, a couple hermits and some frags. He exists on fish food and does no harm, though in the 90g he was responsible for eating some corals. Crabs are opportunistic - they'll eat whatever they can get their claws on - so he's something you definitely want to keep an eye on, and if you can remove him it's probably a good idea.

The Beast actually has a cute little personality and is very shy, and I'm glad I kept him, but he's in a tank where he's free to eat whatever he wants (not the clowns, but they're much larger than he is) - I wouldn't keep any small/vulnerable fish or valuable corals with one of these guys around, just in case

 

[Y-DesygnGuy]

Thanks for the replies I appreciate it. I think I need to find some kind of glass container and get the b@stard to fall into it!