Hairy crab in Acro

[montiel12]

Found a small brown hairy crab in my acro. Should I remove it? I dont have a pic but i will try to put one up soon.

[Pineapple House]

The smooth-shelled crabs found in corals such as Acropora are usually harmless. The hairy brown crabs found in SPS colonies tend to be harmful rather than safe, and can pose a threat to the coral.
Here's quote from Reefs.org Hitchhiker FAQ:

Crabs found in heads of SPS corals are usually of the Family Xanthidae. They are typically commensals which sometimes protect the coral from predatory fish or invertebrates. However, all of these crabs should be watched carefully as not all of the Xanthids are harmless - see below. Trapezia sp. (Family Trapeziidae) is usually found in Pocilloporadae while species such as Tetralia and Domecia (Family Xanthidae) are the typical residents of Acroporidae.(Delbeek and Sprung The Reef Aquarium, Vol. II, pg. 324). In the experience of the author and other reefkeepers that the author has conversed with, hairy brown crabs imported in SPS colonies tend to be harmful rather than commensal, while the tan, smooth shelled crabs like the one in the above picture are peaceful, well-behaved residents.

http://www.reefs.org/hhfaq/img/faq_acrocrab.jpg

A picture would really help. If it is in fact brown and hairy, I would remove it.

Graham

[montiel12]

Thanks for the info. Heres a pic.

[Pineapple House]

I'm not sure about that crab, I can't see it too clearly.

From what I can make out from the picture, the crab looks parasitic. Have you noticed in stress/damage being done to the coral? If so, it may have been the work of the crab. Usually hairy brown crabs found in acropora's are parasitic.

Graham

BTW- Where did you pick up such a specimin of acropora?

[montiel12]

Pick it up at jeffs exotic in Gardena for about 30 bucks.

[montiel12]

Heres a pic of the colony.

[Pineapple House]

Looks nice! Watch out, as the xenia is slowely creeping up on the coral 8)

Graham

BTW- Is the bottom of the colony bleached? Or is that just the way the picture came out?

[phistio]

actually, i think the picture is side ways...and that is refraction from the light above...but i may be mistaken. :oops:

[montiel12]

I took the pic from the top looking down into the tank. The corals not bleaching. Its the pc lighting that i used for the picture that makes it look that way. Ohh ya the xenia is growing fast. Im going to keep an eye on it.

[montiel12]

Found another crab. Man where have these guys been hiding! Is this one parasitic?

[Pineapple House]

The one you just pictured is completely harmless :-D I have about 4 of them hosting in a Humilis. If they're flat shelled, they're most likely harmless.

Graham