Crab ID Please

gistsc · 09/23/2007, 06:28 PM

I'm sorry for the poor quality of the photos, but I do not have a macro lens for my camera yet. The crab was notice for the first time today in a seven month old reef. He appears to have pinchers like a Matrix crab. Overall brownish color, with black and white stripped legs. He seemed interested in eating the meaty foods I had just feed the tank. Any help would be appreciated.

coryjac0b · 09/23/2007, 07:07 PM

i've heard before that crabs with pincers like that are mostly algea eaters and are ok, and that ones with pincers that look otherwise are bad.

just what i heard.

m2434 · 09/23/2007, 07:09 PM

Don't know. Dosn't look reef-safe; does it have flippers?

fazgood · 09/23/2007, 07:25 PM

Probably bad and certainly not worth the risk. The way I tested was I put some fish meat (silver sides) near the hole where mine was living. It was gone in minutes. That told me it would probably grab a fish so I got him out of there. Really bad illustration below.

http://faszl.com/Reef/crabtrap/crabtrap.htm

http://faszl.com/Reef/crabtrap/crab.htm

Faz

speccialj922 · 09/23/2007, 08:30 PM

for the most part, "hairy crabs" are usually no good (not reef safe at least). I would get rid of him just to be safe.

gistsc · 09/23/2007, 10:25 PM

Thank you, I think for now I will leave him in the tank. It is a seven-month-old reef and nothing has been added for some time. So, he has been in there for a while. I will watch him closely. If any one has, a positive Id it is still appreciated.

Sepeku · 09/24/2007, 06:38 AM

Cool gistc, I'd just feed him on occasion too and try a live and let live approach.

I really applaud leaving him in the tank and not out right killing him.

And I don't think feeding silversides is a good way to determine whether or not the crab will eat fish. If eating silversides was proof that it was a fish killer, my hermit crabs, Nassarius snails, and red starfish are potential murderers.
So would the blue tang... but then that fish eats anything.

fazgood · 09/24/2007, 09:09 AM

Eating meat alone is not a good measure of risk. I should have elaborated on my logic... Thanks to Monty Python

"So, logically...
If... she... weighs... the same as a duck,... she's made of wood.
And therefore?
A witch! "

In my case a search showed that my hitchhiker looked like a gorilla crab, came from Florida live rocks and ate fish.. Therefore... A witch! (gorilla crab). I have a red Mithrax and an emerald and I have not seen them eat anything but algae. I have seen the Mithrax step over silversides to get to more green stuff. Gorillas, if that is what it is, can get large enough to catch fish and shrimp and eat them, especially at night. Everything I read said it is best to get them out before they have a chance to do damage. It all depends on what it will be sharing the tank with. I could not believe how easy it was to catch it using this method. It took all of about 2 hours one night.

Not to thread hijack but what type of starfish do you have? I have a red and I never see it eat but it seems just fine. Always thought it was eating algae. I believe I have a Red Bali Star.

Faz

09/23/2007, 06:28 PM	#1
gistsc Registered Member Join Date: Sep 2006 Location: California, USA Posts: 131	Crab ID Please I'm sorry for the poor quality of the photos, but I do not have a macro lens for my camera yet. The crab was notice for the first time today in a seven month old reef. He appears to have pinchers like a Matrix crab. Overall brownish color, with black and white stripped legs. He seemed interested in eating the meaty foods I had just feed the tank. Any help would be appreciated. __________________ 29 gal tank LPS w/10 gal fuge 60 lbs LR Shallow sand bed started 3/1/2007 Current Tank Info: 29 gal reef

09/23/2007, 07:09 PM	#3
m2434 Registered Member Join Date: Jan 2004 Posts: 2,171	Don't know. Dosn't look reef-safe; does it have flippers? __________________ Our imagination is stretched to the utmost, not, as in fiction, to imagine things which are not really there, but just to comprehend those things which are there. ~Richard Feynman

09/23/2007, 07:25 PM	#4
fazgood Not Quite Right Join Date: Aug 2003 Location: Ballwin MO Posts: 1,093	Looks like a gorilla Probably bad and certainly not worth the risk. The way I tested was I put some fish meat (silver sides) near the hole where mine was living. It was gone in minutes. That told me it would probably grab a fish so I got him out of there. Really bad illustration below. http://faszl.com/Reef/crabtrap/crabtrap.htm http://faszl.com/Reef/crabtrap/crab.htm Faz

09/23/2007, 08:30 PM	#5
speccialj922 Registered Member Join Date: Dec 2003 Location: maryland Posts: 1,737	for the most part, "hairy crabs" are usually no good (not reef safe at least). I would get rid of him just to be safe. __________________ Dumb enough to get rid of my tank 33g hex flatback in my classroom.

09/23/2007, 10:25 PM	#6
gistsc Registered Member Join Date: Sep 2006 Location: California, USA Posts: 131	Thank you, I think for now I will leave him in the tank. It is a seven-month-old reef and nothing has been added for some time. So, he has been in there for a while. I will watch him closely. If any one has, a positive Id it is still appreciated. __________________ 29 gal tank LPS w/10 gal fuge 60 lbs LR Shallow sand bed started 3/1/2007 Current Tank Info: 29 gal reef

09/23/2007, 07:07 PM	#2
coryjac0b Registered Member Join Date: Jan 2006 Location: Metairie, LA Posts: 823	i've heard before that crabs with pincers like that are mostly algea eaters and are ok, and that ones with pincers that look otherwise are bad. just what i heard.

09/24/2007, 06:38 AM	#7
Sepeku Registered Member Join Date: Jan 2007 Location: Memphis, TN Posts: 356	Cool gistc, I'd just feed him on occasion too and try a live and let live approach. I really applaud leaving him in the tank and not out right killing him. And I don't think feeding silversides is a good way to determine whether or not the crab will eat fish. If eating silversides was proof that it was a fish killer, my hermit crabs, Nassarius snails, and red starfish are potential murderers. So would the blue tang... but then that fish eats anything.

09/24/2007, 09:09 AM	#8
fazgood Not Quite Right Join Date: Aug 2003 Location: Ballwin MO Posts: 1,093	Agreed Eating meat alone is not a good measure of risk. I should have elaborated on my logic... Thanks to Monty Python "So, logically... If... she... weighs... the same as a duck,... she's made of wood. And therefore? A witch! " In my case a search showed that my hitchhiker looked like a gorilla crab, came from Florida live rocks and ate fish.. Therefore... A witch! (gorilla crab). I have a red Mithrax and an emerald and I have not seen them eat anything but algae. I have seen the Mithrax step over silversides to get to more green stuff. Gorillas, if that is what it is, can get large enough to catch fish and shrimp and eat them, especially at night. Everything I read said it is best to get them out before they have a chance to do damage. It all depends on what it will be sharing the tank with. I could not believe how easy it was to catch it using this method. It took all of about 2 hours one night. Not to thread hijack but what type of starfish do you have? I have a red and I never see it eat but it seems just fine. Always thought it was eating algae. I believe I have a Red Bali Star. Faz