I have a univited guest

[Cruella]

well at first i thought it was a mantis shrimp. but after luring him with some food it looks like some crab. he is living in the rocks. he almost looks like a fiddler crab.he is red and white, spider looking with a big claw. any idea on what he is. i can't get a pic b/c he is in a hole in the rock.

[jallard]

very few crabs are good so IMO i'd evict him

[Sk8r]

Even fewer crabs with really big claws are good. My little emerald, small as a dime, can crunch coralline with her little claws. I'd hate to think what a larger one could do.

[Cruella]

he looks like an emerald crabbut he is rust color. he has the same size claws as an emerald. Ihe has been in there for a few months now and no problems. he is very shy and lives in his little hole. I have an emerald crab who is bigger then a quarter and he is fine, never bothers anyone. I can't get a pic, the crab is small. the size of a dime at the most.

[Dave ESPI]

you have any man made caribbian rock in your tank ?

There is a species that is similar to the green emeralds that is completely harmless.

[shan820]

sounds like a porcelain crab?? common hitch hiker. harmless.

[Dave ESPI]

Mithrax forceps , Red-Ridged Clinging Crab. Family Majidae. Tropical west Atlantic. 1/2-1". Here clinging to a piling at night off Bonaire.

Lookie likie thisie ?

http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/Mithrax%20forceps%20BONnght.jpg