FAQs about Marine Crab (Including some Anomurans)
Related Articles: Crabs, Hermit
Related FAQs: SW Crab Identification 1, SW Crab ID 2, SW Crab ID 3, SW Crab ID 4,
SW Crab ID 5,
Crab ID 6, Marine Crab ID 7,
Marine Crab ID 8, Marine Crab ID 9, Marine
Crab ID 10, Marine
Crab ID 11, Marine
Crab ID 12, SW Crab ID 13,
SW Crab ID 14, SW Crab ID 15, SW
Crab ID 16, SW Crab ID 17,
SW Crab ID 18, SW Crab ID 19,
SW Crab ID 21,
& Marine Invertebrate
identification, Marine Crabs
1, Marine Crabs
2, Marine Crabs 3, Marine Crabs 4, & Crab Behavior, Marine Crab
Selection, Marine Crab
Compatibility, Marine Crab
Systems, Marine Crab
Feeding, Marine Crab
Reproduction, Marine Crab
Amphipods, Copepods, Mysids, Hermit
Banded Coral Shrimp,
Anemone Eating Shrimp,
Systems, Crustacean Feeding,
Hitchhiker ID 11/17/14
What in the world kind of crab is this?? He just showed up one day!
Can't find anything on him!
<Mmm; this 6 kB file is too small to make out much.... could/would you
send along one of a few hundred kBs? Are the ends of the claws of this
animal black/ish? My (family) guess is on the Xanthidae... See WWM, the
Net re. Bob Fenner>
Re: Hitchhiker ID
<Ten megs of the same non-cropped image. Lose. Read through WWM. B>
Okay so I got a few more pictures. Hopefully they are a little better.
He has darkened tips of his claws while the arms are white. He does look
similar to that family in that he has a very rounded shell in the front.
Crab ID please. No pic
Hi again crew,
Thanks for answering my question yesterday, you helped me out.
Today I have another question if it's ok.
I found a baby crab in my live rock last night and was able to get it
out for identification but can't see no pictures of crabs like this on
What I'd like to know is if it is reef safe or not, how big they get and
what they feed on.
I know it came when I brought my live rock, either as an egg or baby!
Thanks in advance,
<Mmm; do you have an image? None found attached here. Bob Fenner>
Crab ID. Picture
Sorry, forgot to add a picture of the crab I'd like ID'ing!
<Ah; a small Xanthid by the looks.... see here:
about 5, 6 responses down. Best to remove. BobF>
Re: Crab ID. Picture
Thanks for replying once again, I'm going to be making a donation to you
guy's, such a good site.
<I/we thank you>
I have the crab out of the aquarium now but not sure what to do with it, do
I try giving it away/back to my LFS or I hate to say, kill it!?
<Mmm; do you have a sump, refugium? Smallish tank that it can live in apart?
I would try the LFS if not>
Re: Crab ID. Picture
Just gave a small donation, hope it helps keep things running.
<Every bit does>
I have no sump or refugium either, I'm going to set up a small tank with a
sponge filter and heater to see how he/she gets on.
Thanks again for your advice
I know the quality of photos is not great, I found this crab under my
Tubastrea micanthra, it did have pincers but lost them whilst being
removed, they looked a bit sharp. Please can you identify what crab it
Is there likely more?
<The pix are too small, poorly resolved... B>
|Re: Crab identification
I thought that would be the case, I have been looking through your crab
identifications and it looks identical to a squat lobster
which someone else also found on their sun coral, are they reef
<Very much so>
Do they live in sun corals and are they commensal? I don't trust crabs at
<Mmm; well; these aren't "true" crabs... BobF>
After browsing your past ID articles, would you guess this guy to be a
“Red Rock Crab”?
<Away from my ref. works... out in Ft. Myers giving a talk in FLA...
Looks to be a Xanthid... of the genus Atergatis. Bob Fenner>
Thanks for your thoughts
Unidentified Crab ID 1/20/14
Lynn; any idea? B
Re: Unidentified Crab ID 1/20/14
Well, it does look a lot like the crab I tentatively ID'd in the 2011
query, but unfortunately I don't have anything to add to it. I
think Wesley is looking for corroboration on whether you agree with what
I've already written. The only other thing I could add would be to
again, advise that the crab be moved. If I were in his position,
I'd move it to one of the empty compartments he mentioned, supply some
rubble and offer the crab the occasional sinking food pellet and/or bit
of shrimp/fish/clam, etc.. Hope that helps! Take care, LynnZ
<Thank you Lynn; I do concur. BobF>
Unidentified Crab ID 1/21/14
Dear WWM crew,
I recently bought a Montipora frag for my tank, and have caught a little
hitch-hiker crab living between two of the coral's plates! Trawling your
extensive database for a positive ID match is probably becoming similar
to navigating a reef but Google did help me to find a picture on one of
your FAQs that seems to match what I have
(http://www.wetwebmedia.com/SWCrabIDF18 , post marked 3/30/11). I have
attached some photos to this email; would you be able to tell me if you
<I do... this is likely a Xanthid, possible Chlorodiella sp.>
The post advises such crabs ought to be rehomed. My tank is a
stand-alone, so it doesn't have a sump, but it does have a rear portion
divided into four compartments; two are occupied by a skimmer and return
pump. If I put the crab directly into one of the empty compartments, is
it likely to get enough food, or should I put something else in there
too to give it
something to graze on, like a few rubble pieces?
<The rubble and separation are good ideas>
Thanks for your help,
<Welcome. Bob Fenner & Lynn Zurik>
Small Crab, ID guesses from poor pix
Hi and Happy New Year!
<And you Barbara>
I have a FOWLR tank with aggressive species, triggers,
tangs, a clarkii and LTA. I also have a Lawn mower Blenny and a Spotted
Hawk . I have never seen anything else in my tank but pods in the
over flow area. To my surprise this morning I saw this dead crab
in the bottom of my sand bed.
<Ah; such surprises do "happen">
I pulled it out and took a picture. Since it wasn't eaten I am wondering
if it might be a molt. The size fits on the tip of my finger. I guess if
it is a molt then I have a crab! It looks like a Pink dotted
What do you think? Sorry if the picture isn't clear.
<Might be a Xanthid... need a better pic... Am surprised your triggers
didn't ingest it! Cheers, Bob Fenner>
|Re: Small Crab
I was very surprised too. I moved it to
a darker background and took another
picture. If it is a Xanthid how
big do they grow. Is this an adult?
Do they molt their entire bodies because
I think this might just be a shell??
<Do molt all exoskeleton>
<... still can't make out details; not
seen a crab of this family stay this