A tiny black headed fish with purple body has appeared from the new live rock i put in my tank, what is it?

I recently bought live rock for my new saltwater aquarium, but i have discovered a tiny black headed fish with a purple body and a crab with red eyed a furry legs living in the tank. What are these and are the safe?A tiny black headed fish with purple body has appeared from the new live rock i put in my tank, what is it?
http://www.marinecenter.com/fish/basslet鈥?/a>





Is this what it looks like? Yep it is a basslets. Excellent hiders. He will be fine in your tank, and even in a reef tank.





Crab will add to your clean up crew. Don't be suprised if there are more cridders hiding either. This is the reason why most live rock is already cured and really should not be recured when purchased.





They are both safe in the tank. Lucky youA tiny black headed fish with purple body has appeared from the new live rock i put in my tank, what is it?
Here is one guess on the fish. It could be a Black Cap Basslet. Don't get more since it's territorial. They sell for $60 each. Ok, maybe you will want to breed them. Heh.





As far as your crab goes, it could be an acro crab. Those are waste eaters and they stay small.






try and take some pics for us so we can tell you?