ID another critter?

Bertico78 · 07/21/2008, 08:48 PM

Just found this new "stowaway" in the tank. Anyone know what type of crab that is and if it's beneficial or detrimental to a FOWLR tank?
Thanks!

billie6227 · 07/21/2008, 09:14 PM

Looks like a porcelain crab, and those are reef safe.

Aquarist007 · 07/21/2008, 09:22 PM

check here---I think it is an xanthid crab

http://www.melevsreef.com/id/crabs.html

paraletho · 07/21/2008, 10:21 PM

I think Capn is on the right track looks more Xanthid to me (Mud crabs or rubble crabs). They sit more upright on their legs with the carapace tilted down in back. Exact species ?

greenbean36191 · 07/22/2008, 06:02 AM

Neither of the above. Porcelain crabs aren't "true" crabs and they have 6 walking legs rather than the regular 8 of true crabs. Xanthids usually have black tipped claws, but the dead giveaway here is the stance with the legs splayed out as well as the body that's narrower at the back than the front. It's a grapsid, or clinging crab, of some sort. You're almost certainly not going to be able to get it identified to species. Even for adult crabs that's almost impossible in most cases without consulting a specialist. For juveniles, even then it might be impossible.

Some of these guys are fine, and may be commensal on benthic critters. Others are pretty destructive, especially as they get bigger. Personally I never trust any crabs since they're almost all opportunistic.

07/21/2008, 08:48 PM	#1
Bertico78 Registered Member Join Date: Nov 2003 Location: Miami Posts: 25	ID another critter? Just found this new "stowaway" in the tank. Anyone know what type of crab that is and if it's beneficial or detrimental to a FOWLR tank? Thanks!

07/21/2008, 09:22 PM	#3
Aquarist007 Registered Member Join Date: Apr 2007 Location: Hamilton, Canada Posts: 28,240 Blog Entries: 1	check here---I think it is an xanthid crab http://www.melevsreef.com/id/crabs.html __________________ I prefer my substrates stirred but not shaken Current Tank Info: 150gal long mixed reef, 90gal sump, 60 gal refugium with 200 lbs live rock

07/22/2008, 06:02 AM	#5
greenbean36191 Premium Member Join Date: Jun 2003 Location: Ft. Lauderdale Posts: 10,598	Neither of the above. Porcelain crabs aren't "true" crabs and they have 6 walking legs rather than the regular 8 of true crabs. Xanthids usually have black tipped claws, but the dead giveaway here is the stance with the legs splayed out as well as the body that's narrower at the back than the front. It's a grapsid, or clinging crab, of some sort. You're almost certainly not going to be able to get it identified to species. Even for adult crabs that's almost impossible in most cases without consulting a specialist. For juveniles, even then it might be impossible. Some of these guys are fine, and may be commensal on benthic critters. Others are pretty destructive, especially as they get bigger. Personally I never trust any crabs since they're almost all opportunistic. __________________ Some say the sun rises in the East. Some say it rises in the West. The truth must be somewhere in the middle. Current Tank Info: tore them down to move and haven't had the time or money to set them back up

07/21/2008, 09:14 PM	#2
billie6227 Registered Member Join Date: Dec 2007 Location: Fort Worth TX Posts: 129	Looks like a porcelain crab, and those are reef safe.

07/21/2008, 10:21 PM	#4
paraletho Premium Member Join Date: Jul 2008 Location: Sabine Pass TX Posts: 433	I think Capn is on the right track looks more Xanthid to me (Mud crabs or rubble crabs). They sit more upright on their legs with the carapace tilted down in back. Exact species ?