I,ve just been watching my tank after lights went out and a small crab popped out of the rock, It was about half an inch across brown and white coulourings with hairs on its legs also one of its front claws was alot bigger than the other. He was only out for a few seconds it picked up a dead mysis shrimp and scutled off before I could find my camera
I,ve had a look through google pics but couldn,t find any thing similar any ideas
If you go to the first link and go down the page until you reach the image shown in the second link I have posted then you will get the description of the crab coz the image is rubbish!!
My crab is more of a pale brown and cream colour on reflection ( it would be well cammouflaged on the sand)and the large claw is alot more pronounced than the crab in the photo. More like a hermit crab difference in size on the claw and the pincers where a dark red/brown it is very similar in colouration and claw size to the staghorn hermit crab on liveaquaria.com but with out the branching shell with the normal crab shape.
I,ll have to get my camera out after work today and see if I can catch a picture of it