Mystery Crab - 08/11/2005
Hi
<Hello.>
Today I Purchased some live rock and in it came out a really sweet little bright red crab around 1inch across and scarlet red in colour have you any ideas what it could be.  It buried itself in the sand substrate.  The rock is Fiji rock.
<Many, many possibilities....  See here for starters:  http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/swcrabs.htm . >
Regards,  Charlotte,  In the UK
<Wising you well,  -Sabrina, in sunny silicon valley, CA, USofA.>

Red crab....  possibly from Fiji.... ? 8/13/05
Hey there, Bobster....
Quick question.  The gal with a (very) undetailed crab
ID request yesterday has replied, and given a
(slightly) more detailed description....  Wonder if
you can point me in the right direction....
<Saw this... and with the provided info... don't know...>
She say it has roughly the shape of Cancer antennarius
. It has elongated black eyestalks and black "joints".
It is currently about an inch across.
The crab has burrowed into the substrate, and come
back out again.
It came in on Fiji live rock that she recently added,
but I am not at all convinced that that means the crab
originated with the rock from Fiji.  Don't know.
<Me neither>
Anyhu, the elongated eyestalks thing and small size,
as well as burrowing, makes me think Uca/fiddler-type
crab....  a couple red ones I know of/have seen....
but I really don't know.
Any thoughts?
-Sabrina
<Really am at a loss... not an unusual state here... I say (re such crab
unknowns), "When in doubt, take it out" or at least keep a keen eye on it
for opportunistic predation. Cheers, BobF>

Mystery Crab - III - 08/12/2005
Dear Sabrina,
<Hi, Charlotte!>
The crab I have looks very much like Cancer antennarius although it is very small and scarlet red not brown. I present it is about 1inch across.  The crab has finally come out of the sand substrate. It is still bright red with a smooth shell, the eyes are on long black stalks also it has black joints.  Hope this is still some help because there was nothing like it on the list you sent other than the one I labeled.
Regards
Charlotte Windsor
<This description is of some small help, but unfortunately, just not enough for an accurate ID....  You might google for images of genus "Uca", but I do not know if that will be fruitful at all.  I asked Bob his ideas, as well; he, too, is at a loss.  He suggests " 'When in doubt, take it out' or at least keep a keen eye on
it for opportunistic predation."  So do be wary of it - were it me, I would probably set up another small tank for the guy, should he prove to be a problem.  Wishing you well,  -Sabrina>

Mystery Crab - IV - 08/12/2005
Hi Sabrina
<Hello, Charlotte.>
Would a photo of the little guy help ?
<Mm, not terribly likely, but it sure wouldn't hurt!  We may *possibly* be able to nail it down a little....  Worth a shot.>
Charlotte
<Wishing you well,  -Sabrina>

Crab ID 7/28/05
WWM Crew
<Mike G>
I have spent hours looking for what the ID of the crab
<Good luck. Crab identification is very difficult, indeed.>
I have in the attached photo is, and anything that I could find out about it.
<I'm sorry, we didn't receive a photo.>
I have a 125 gal, some coral reef with 100 lbs of live rock and a few fish, he appears he could be a mean little fellow, and I do not have any idea how big he will get.
<In general, I don't trust crabs. Guilty until proven innocent is what I think of em. I'd isolate him until you can prove him either innocent or guilty.>
Thanks for your help in advance
<Welcome.>
Mike

Re: Crab ID 7/28/05
Sorry I did not attach the first time, thanks for your timely first response, maybe you can give me more info with this, thanks again, Mike
<Still did not receive it. Mike G>

Hitchhiker Crab; I am not sure which it is; hair algae and do you know Kenny Doubt, aka 'Sharkbite'? 7/17/05
Hello Bob.
<James>
I made a discovery as I brought my live rock home from my favorite LFS the
other day. I now have another crab. I was fortunate not to have put my
fingers into the hole he was hiding in and noticed it while I was examining
the rock. It is somewhat large and I estimate nearly an inch and a ˝ across
the carapace. It is black or a very dark green and the joints appear white.
I am not certain, nor is the owner of LFS, if it came from his tank or not.
This is because we got rock from both the holding/curing area and then some
from a main tank. This specimen neither seems to bother the skunk cleaner
shrimp, which I transferred in from the 5 gallon, nor the red scooter
blennies. How do I go about looking up what this crab is?
<Mmm, a pic... the Net... sending out to forums that deal with such>
I do not see it
much but I know where his hiding spot is. It seems to be content to pick at
the rock and only raises its claws when anything gets into its comfort zone;
standing ground but does not appear overtly aggressive. I am going to try
and catch it and bring it to the LFS to see if he can identify it. If it was
in his tank I will probably keep it and pay him something extra as it has
lived peacefully in that tank for years and did not bother the fish that are
in it. If it is not his then it is a mystery and came from the tank he broke
down from a customer and I think not worth the risk.  
I also made a discovery in that the branched coral (somewhat obviously now
is coral) looking rock had corals coming out the tips. They are red and dark
purple, bubble-like in appearance. This is going to be somewhat more of an
issue as unless I can get a decent picture I know if I remove it from the
tank and take it the store odds are good it will be a day or so before they
will open back out. Besides, I do not wish to stress them. I do want to take
care of them properly and I feel that is easiest a task if I know just what
they are.
I was speaking with JJ Perez the other day at his store in Ridgefield Park,
NJ. We thinks the problem (algal growth) I have is with phosphates and hard
Garfield water. He mentioned the hardness of the water (he measured at about
550ppm KH a while back)
<Yikes, liquid rock!>
was great for breeding African Cichlids. I have
limited the lighting time periods and tried reducing feeding. I have been
diligent in trying to pick as much of this hairy nuisance as I can off the
rock but unless I get it out it just sticks elsewhere. We (my wife and I)
have decided on getting a small RO unit but have not yet. The Mithrax crab
is not doing his job in the 5 gallon tank as the Royal Gramma pursues him
mercilessly once he is seen out of his hiding spots deep in the rock. The
cleaner shrimp was removed as the fish was constantly picking at him though
I would have preferred to wait to add him into the 55gallon tank. It is nice
to see him no longer forced to hide in the top corner near the heater all
the time and this does make cleaning the smaller tank easier.
I think I asked about Kenny in an earlier email (now like all things on my
old drive) lost. JJ mentioned that he was a fish collector and worked at a
distributor in Hawaii. I just thought he was a cool surfer originally from
New Jersey. Small world indeed!
<Don't know him as far as I'm aware... do think I've been to the NJ store with my bro-in-law Pat though.  Bob Fenner>
Present (mostly constant) tank parameters:
pH:       8.2-8.4
SG:      1.0228 (55 gallon) 1.0224 (5 gallon)
KH:       upwards of 300ppm (see JJ’s measurement above)
NO2-:    0ppm
NO3+:   15-20ppm (55 gallon) 20 ppm (5 gallon)
Temp:   78-79F average.
Gear on the 55 Gallon: 260 Watt Coralife power compact, Aquaclear 1100
filter and a Penguin 1140 Power Head (directing flow diagonally towards the
front of the tank) mounted on the left end from the filter which is on the
right/middle side. Prizm protein skimmer not hooked up yet (I am thinking of
placing it next to the filter if it will fit) as per recommendation (wait
three weeks) from using stress coat to treat the tap water for metals and Cl
ions. Oh, yes I am running everything off a GFCI… Stanley makes a good one
available at Home Depot and it has 8 plug inputs for about $27. I am also
going to get a UPS… because you never know when you may not have power…
Any suggestions on things I should change or add?
Thank you for making such a great website and providing so much great
information in your book (wife calls it my ‘fish bible’, lol) Bob.
James Zimmer

Unidentified crab type creature
Hello All,
I just bought a yellow and purple double sea-squirt from live Aquaria.com (Polycarpa aurata). It came with some interesting hitchhikers on the small rock it is attached to. What seems to be a Christmas tree worm or some such double barreled triple banded fan worm.
However, what I am interested in ID'ing is some sort of crab I think. Unfortunately it is much too small for me to get a picture of (I need a telephoto lens). There are at least 5 in close proximity. They live in very well defined holes. All that sticks out is a pair of eye stalks, somewhat like a hermit crab, two long antennae, and some funny pincers. One is predominately larger than the other, but both are very flattish with a purplish color and small white spots that blend into coralline algae as great camouflage. The pincers are very flat and kind of wide and bladelike like a canoe paddle blade. They have a funny behavior of resting their pincers hanging out the edge of the hole like they are relaxing on their balcony or something.  All of them do this. Again, all I can see are the eyes, antennae and pincers. The whole critter is very small.  Because of the shape of the whole its body must be more tube like than a typical round crab shape.   The pincer length of the largest one is only about 2 mm. The antenna are maybe 4 mm's in length. I don't know how long the whole crabs are because they won't come out of their hole.
Anyway...any help would be appreciated...Collin
>>>Greetings Collin,
Even if I were the worlds foremost crab expert, I could hardly hope to identify the species you have in your possession with such a description. There are THOUSANDS of species, positive identification is often difficult even with the best of photos.
In all likelihood they are harmless, very rarely have I had problems with crabs unless they were fairly large.
Cheers
Jim<<<

Caribbean Crab ID
Greetings,
I am seeking assistance in identifying a crab that surfed his way in on a
piece of Caribbean live rock.  We have seen glimpses of him here and
there, but never enough to know whether we had a Mantis Shrimp or
something else.  We were finally able to get him out of his hole, and were
surprised to see a crab.  If he is non-threatening, I will return him to
the rock.  Currently, we only have Astraea snails, Nassarius snails,
Blue-leg Hermits, and a pair of Yellow-Tail Damsels.
Thank you in advance,
Brian Domke
>>Hi Brian. I don't actually know what it is, but a good rule of thumb is not to put it back in the tank. Most crustaceans are opportunistic carnivores and probably will, at some point, eat something you want.
Rich>>

Filter feeding crab
hey guys the other day I was strolling thru the LFS and noticed this crab that had arms that were modified for filter feeding (really cool) I couldn't keep my eyes off it.   of course the employees didn't know what it was, any ideas? << An anemone crab, maybe a Neopetrolisthes maculata. >>
thanks, Ryan
<<  Blundell  >>