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FAQs about Marine Crab (Including some Anomurans) Identification 20

Related Articles: Crabs, Hermit Crabs,

Related FAQs: SW Crab Identification 1, SW Crab ID 2, SW Crab ID 3, SW Crab ID 4, SW Crab ID 5, SW 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, Crab ID 22, & 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 Disease, Micro-Crustaceans, Amphipods, Copepods, Mysids, Hermit Crabs, Shrimps, Cleaner Shrimps, Banded Coral Shrimp, Mantis Shrimp, Anemone Eating Shrimp, Crustacean Identification, Crustacean Selection, Crustacean Behavior, Crustacean Compatibility, Crustacean Systems, Crustacean Feeding, Crustacean Disease, Crustacean Reproduction,

Crab ID        5/20/15
Good morning,
<Sorry for the delay; been out>
I was needing an ID on a hitch hiker crab. He was found eating Zoas and Palys while rearranging rock and frag plugs at night in a friends tank.
My friend caught him and I took him in in my sump. I was thinking calico crab but wanted a positive ID, could you help? I have attached some pictures.
Thanks in advance,
Angela Parsell
<Mmm; need better (more resolved, closer up) pix; but I would do as you've done: Isolated this specimen... too likely to eat most all in your main/display system in time. Bob Fenner>

Re: Crab ID        5/21/15
These are the best I have. He's hidden in my sump and cant find him. He does have black claws. Do these pictures work?
<A Xanthid likely.... you have scanned through the WWM Crab ID FAQs....?

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     11/17/14
<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    8/21/14
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 your site.
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,
Ady peters
<Mmm; do you have an image? None found attached here. Bob Fenner>
Crab ID. Picture

Hi again,
Sorry, forgot to add a picture of the crab I'd like ID'ing!
<Ah; a small Xanthid by the looks.... see here: http://www.wetwebmedia.com/swcrabidfaq5.htm
about 5, 6 responses down. Best to remove. BobF>
Ady peters

Re: Crab ID. Picture    8/21/14
<Ms. A>
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>
<Welcome. BobF>
Re: Crab ID. Picture
Me again,
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.
<Ah, good>
Thanks again for your advice
Ady peters

Crab identification   5/7/14
Hi Bob,
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?
Is there likely more?
<The pix are too small, poorly resolved... B>

Re: Crab identification   5/7/14
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 safe?
<Very much so>

Do they live in sun corals and are they commensal? I don't trust crabs at all!
<Mmm; well; these aren't "true" crabs... BobF>

Crab ID      4/11/14
Hi Crew,
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

Hi Bob,
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 agree?
<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      1/1/14
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 Xanthiden Crab. 
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     1/1/14
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>
Warm regards,
<... still can't make out details; not seen a crab of this family stay this small. BobF> 

Worm & Crab ID      8/18/13
I have spent hours on your site and Google.com trying to ID these creatures.  The worm(s) are dark then a small white section then a more grayish color.  Very tiny worm like creatures.  Those are Nerite eggs on the glass and they are about the size of one or two eggs. 
 <Looks to be some sort of flatworm; "Planaria" sort... not likely a worry>
The two crabs are two separate creatures I find at night roaming my tank. 
I think they are both the same species, but not absolutely sure.  I have found the molt from crab, but it was a bit bigger than either of these creatures.
I'm not sure if I have anything to worry about.
<General opportunistic omnivores; judging from their claws... are consuming some life in your system; more as time goes by... I'd be reading re Decapod compatibility on WWM>
 Our tank has not been at its best due to our special needs two year old. 
She is doing much better now giving us much more time for our water critters. 
 Thanks a Ton,
<Welcome. Bob Fenner> 

full size pic.
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