Please help ID this crab hitchhiker

CruxOp · 02/12/2015, 01:53 PM

i found this guy hitchhiking inside of a stylophora - i haven't been able to find any acro crabs that look like him and am stumped about whether he is good or bad. Can someone please help?

Huge thanks in advance

Compliance · 02/12/2015, 02:20 PM

literally 'inside' the coral?

So you snapped it and he was in there - or just inbetween the branches?

Either way - i don't recognize it specifically but it's TINY so it may be a case of a change of appearance as it gets older....

cloak · 02/12/2015, 02:22 PM

Gall crab?

snorvich · 02/12/2015, 02:38 PM

Blue eyes?

CruxOp · 02/12/2015, 02:55 PM

Wow - i think you nailed it. I researched gall crabs and found some info that points to him being bad. He was inside of a hollowed out section of the frag that looks exactly like the picture attached. That being said, it seems like they're considered a pest so I should get rid of him - correct?

Fade2White12 · 02/12/2015, 03:07 PM

Based on the abdomen shape, I'd be inclined to think it was a Gall crab. They really will not damage corals. And I think they're pretty cool.

If you found the crab literally inside the coral, it is probably a female. They're pretty much limited to filter feeding and snacking on mucus and algae near the opening. Males are a lot more "free roaming" but have similar diets.

Personally, I'd put it back, assuming someone can give a definitive ID. Could you put it in a container in the water? It's a little hard to tell when it's out of water.

CruxOp · 02/12/2015, 03:57 PM

Hi Snorvich - eyes are not blue.

CruxOp · 02/12/2015, 04:00 PM

All - here is a pic of the crab in water. Please let me know what you think.

CruxOp · 02/12/2015, 04:04 PM

attachment

CruxOp · 02/12/2015, 04:09 PM

Super closeup

FraggledRock · 02/12/2015, 04:10 PM

baby emerald?

CruxOp · 02/12/2015, 04:19 PM

i think the shape is wrong to be an emerald, plus the way it was embedded in the coral didn't seem emerald-y

Fade2White12 · 02/17/2015, 09:28 AM

Sorry for the late reply, but that's absolutely a gall crab.

I know some people (inaccurately) claim that they have killed certain corals, but that's just not true. It does the crab no good for the coral it lives in to perish. It's a pretty cool critter, IMO.

CruxOp · 02/18/2015, 03:30 PM

Thanks for the positive ID - I went back and forth before you responded and ended up putting her in the tank with the coral. She's a very well-behaved tank mate, just sits at the base of the coral all day. Fascinating little creature!

02/12/2015, 02:38 PM	#4
snorvich Team RC member Join Date: Aug 2005 Location: Outlander Posts: 40,953 Blog Entries: 46	Blue eyes? __________________ Warmest regards, ~Steve~

02/12/2015, 04:10 PM	#11
FraggledRock Registered Member Join Date: Dec 2014 Location: New York, New York Posts: 2,185	baby emerald? __________________ “For most of history, man has had to fight nature to survive; in this century he is beginning to realize that, in order to survive, he must protect it.”― Jacques-Yves Cousteau MarineBio.org Current Tank Info: 40 Gallon Breeder w/ Bean Animal Overflow 20G Sump, Mixed Reef.

02/12/2015, 02:20 PM	#2
Compliance Registered Member Join Date: Jan 2015 Posts: 144	literally 'inside' the coral? So you snapped it and he was in there - or just inbetween the branches? Either way - i don't recognize it specifically but it's TINY so it may be a case of a change of appearance as it gets older....

02/12/2015, 02:22 PM	#3
cloak Moved On Join Date: Jul 2000 Location: Stockton, CA Posts: 14,854	Gall crab?

02/12/2015, 03:07 PM	#6
Fade2White12 Registered Member Join Date: Oct 2007 Posts: 271	Based on the abdomen shape, I'd be inclined to think it was a Gall crab. They really will not damage corals. And I think they're pretty cool. If you found the crab literally inside the coral, it is probably a female. They're pretty much limited to filter feeding and snacking on mucus and algae near the opening. Males are a lot more "free roaming" but have similar diets. Personally, I'd put it back, assuming someone can give a definitive ID. Could you put it in a container in the water? It's a little hard to tell when it's out of water.

02/12/2015, 03:57 PM	#7
CruxOp Registered Member Join Date: Oct 2009 Posts: 14	Hi Snorvich - eyes are not blue.

02/12/2015, 04:00 PM	#8
CruxOp Registered Member Join Date: Oct 2009 Posts: 14	All - here is a pic of the crab in water. Please let me know what you think.

02/12/2015, 04:19 PM	#12
CruxOp Registered Member Join Date: Oct 2009 Posts: 14	i think the shape is wrong to be an emerald, plus the way it was embedded in the coral didn't seem emerald-y

02/17/2015, 09:28 AM	#13
Fade2White12 Registered Member Join Date: Oct 2007 Posts: 271	Sorry for the late reply, but that's absolutely a gall crab. I know some people (inaccurately) claim that they have killed certain corals, but that's just not true. It does the crab no good for the coral it lives in to perish. It's a pretty cool critter, IMO.

02/18/2015, 03:30 PM	#14
CruxOp Registered Member Join Date: Oct 2009 Posts: 14	Thanks for the positive ID - I went back and forth before you responded and ended up putting her in the tank with the coral. She's a very well-behaved tank mate, just sits at the base of the coral all day. Fascinating little creature!