Compatibility/Decorator Crab   03/9/06
Hello WetWebMedia crew, <Hello MR.> We have a 55 gallon tank with 2 tangs (yellow and a 2 inch blue one), 2
damsels, 1 clown, 1 cleaner shrimp, 7 small hermit crabs, 2 anemones, and 1 black cucumber.  (We are going to upgrade to a 90 gallon tank in the summer. ) We recently purchased a decorator crab and are wondering if they are compatible with cucumbers and cleaner shrimp.  The crab is a nice little addition to our tank and he's quite a colorful character.  Our cucumber is quite the explorer,  he likes to go everywhere in the thank and sometimes right next to the decorator crab.  However, I am worried that the crab may hurt the cucumber one of these days, which will cause him to nuke the tank.   As a precaution, we took the crab out and placed him in our quarantine 10
gallon tank until we know he is actually safe.   Could you please email me back at this address with your answer?  <They are not reef safe and by your email I'm assuming it is a fish only tank.  Their activity of placing pieces of sponge, algae, polyps, etc on their back (carapace) will cause some damage to these animals and renders them not reef safe.  Other than that, should be safe with what you have now.>
Thank you so much,<You're welcome. James (Salty Dog)>
MR

Re: Decorator Crab Compatibility  - 03/09/2006
Thank you for the prompt response James. :) <You're welcome.>  Also, I forgot to mention our little incident we had a couple of days ago.  We had 2 clown fish in our tank.  (One of them was looking sickly).  He was still alive when we went to bed, but when we woke up the decorator crab was eating him.  I was wondering if the crab could have caught him and killed him?  I have heard that they kill small fish when they are sleeping.  Is this true?  <Small specimens shouldn't attack fish.  I'm guessing the fish died and the crab came to supper.  James (Salty Dog)>

Atergatis floridus (Hitler Crab)   03/07/06
Hello again,
<Sieg heil!>
            I have a hitchhiker crab in my Indonesian rock that I have identified from pictures as Atergatis floridus. I did a search on
the web and found that its flesh is poisonous if eaten. My wife thinks it killed our cute little Red Scooter Blenny (Synchiropus stellatus)
<Not surprisingly>
that we had in the tank and has named the crab 'Hitler" accordingly.  It was not to be found one morning and she is convinced that "Hitler" is to blame.
<Mmm>
I now think there is a good possibility that this is what happened as well. The Dragonet was doing well for several weeks gorging himself on the
plethora of "Bugs" that inhabit the tank as would any Dragonet. We really miss watching him hop from rock to rock picking at bugs. They really are cute little guys.
Anyway I have been unable to find out if it might eat any of the corals
<Das ist verboten! But might>
I have in the tank which is a LPS Lagoon type tank with a lone Purple Firefish currently being the only vertebrate.
<...>
The Cnidarians are various Euphyllids, Brains and Goniopora. He is surprisingly strong for his size and has pushed some of the corals
(Elegance, Goniopora) around on the sandy bottom where they have been placed. Last night I saw him overturn a large Goniopora once while digging underneath it (probably was
digging for worms I would think).
<Or what have you>
I'm beginning to think my better half is correct in telling me I need to give Hitler the ol Jack Boot in the posterior before it really does some damage.
<Javul, I would>
I'm thinking I could try putting some krill in a large fishnet and hopefully he will go for it and I can lift him out. He is pretty fast and very
cautious so it won't be easy to catch him.
<I have faith in you Colonel>
I have a ten gallon in the basement where I put my Sargassum, Chaetomorpha and other algae trimmings and I was thinking I could put Hitler in there
where he can't hurt anything.
<Worth trying>
I really don't want to kill it even thought my wife has already given Hitler the death sentence.
Thank you,
Bryan D. Gatewood
<Good hunting. Bob Fenner/Klink>

Crab Compatibility?   2/7/06
Hello WWM:
<Frank>
You have been instrumental so far in the health and upkeep of my tank and I'm hoping to take advantage of your services one more time.  I have had a
decorator crab for about 2 months, I think its great and one of the most interesting members of my little community.  As an invert fanatic, I was
also interested in the Hawaiian Strawberry Crab (the site does not provide the scientific name so here is a link to the site if it helps
http://www.saltwaterfish.com/site_11_03/product_info.php?products_id=415&parent_category=4&category search=63&root_parent_id=4).
I know that crabs especially tend to be creatures of opportunity and was wondering how likely these two would be to attack one another.
Sincerely,
Frank
<Mmm, looks like Liomera rugata... a Xanthid... is opportunistic, though small... will "pick" if hungry, there's opportunities. Bob Fenner>
 

Re: Random Mithrax crab death or mating? - The mystery Thickens Like Gumbo  11/11/05
So the mystery thickens.  As I deal with another bout of insomnia I decided to use my time productively on my tank.
<Oooh, good start...>
I set out my mantis trap.  And in doing so decided to feed the tank a little at night and watch.  Well, I saw all sorts of new worms (red and black bristle from 1-4  inches, an earthworm" that was 6 inches, took him out, and some brown worm that looked like the biggest pod ever who popped four inches out of a hole and pulled a freeze dried shrimp down the hole with him in the blink of an eye!).
<Yowzah!>
So here is the mystery.  As I said I had 2 Mithrax crabs.  Guess what.  I still do!  When the worm that grabbed the freeze dried shrimp had it part of the way down the whole, a claw comes out and grabs the shrimp!  
<Ahh, those molting so and so's>
Well because I had be watching, I did a little searching and found that I still had 2 crabs!  So where did the 3rd now dead one come in from?
<Just the shells, man?>
I thought back and realized that the crab that died looked a little funny.  He was hairy, and really more red and white/gray stripped.  He also seemed a little smaller then my Mithrax.  So the mystery deepens.  
I had a random crab who must have been small enough to hide somewhere on my rock during the 8 week curing process and stayed out of sight until today when he died!  I have only added 1 piece of rock since, a rock with my xenia on it.  Except the rock has no crevice big enough for a crab of that size to fit in.
So this is more of an update then anything else.  I love this hobby!  Thanks
for helping me so much in the past. Now I have a new obsession, worms (and
catching that mantis shrimp, the popping is driving me bonkers)!
<Might be an alpheid...>
 I have some unidentified worm I have to send you a photo of.  Looks like a meaty
version of a feather duster, has been on board since I got the rock, has never moved or grown, but today happened to grab a krill out of my tongs and eat the whole thing, which was the size of his entire exposed mouth!
Thanks again.
Marc
<Thanks for the update! Bob Fenner>

Concerns Regarding a Hitchhiker Crab 10/16/05
Hi There,
<Hey, Mike G with you this evening, glad to see the rain has finally cleared up>
Firstly thank you for answering my previous email/post about Clown Eggs.  Now we have another Drama..
<Such is the nature of the hobby.>
We brought some live rock today and added it to our Clown tank. We also have a 20cm Radianthus Anemone. A crab has appeared in the tank, it must have hitched a ride on the live rock from the fish shop!!
<Likely.>
The crab is dark but has striped legs. We noticed the anemone kept shuddering while the clowns were swimming around it, so we had a close look then we first noticed/saw the crab crawl out from near where the anemone was wedged between two rocks. We are concerned that this crab may have been or will pinch the anemone, or damage it in some way. The crab is small 2cm.
<Identifying crabs is a difficult thing to do WITH pictures, without them I'd not hazard a guess.>
But we realize crabs and anemones both live in the sea so they may get along ok? 
<Great White Sharks and, say, damselfish live in the sea, and they don't really get along alright.>
Should we leave the crab in the tank or take it out?
<I'd remove it, just to be on the safe side. If you'd like an ID, get a picture and try asking DR. Ron Shimek on www.rshimek.com or, if you have ReefCentral Account, his forum is good for such cases. He tends to be very, very good at invertebrate ID.>
The crab obviously has its hiding spot right where the anemone is wedged between two rocks so to get the crab out will be hard cause we will have to pull these rocks apart, but the anemone is stuck to both of them. What do we do? 
<Hmmm... Bait a trap?>
Also, will the anemones sting, sting the crab?
<Nope, the crab's exoskeleton will protect it.>
Any help will be appreciated.
Thank You
<Welcome, hope this helps. Mike G> 

Problematic Hitchhiker - 08/21/05
Hello Wet Web Crew!
>>Hi Tina!>>
I attained a fair amount of live rock from a girl who works at a LFS who told me she needed to downsize her tank due to little time.
<<ok>>
I happily accepted her offer for half-price live rock that has been in her tank for a few years and has some decent algae growth on it.  When putting it into the tank, I found that the live rock wasn't all I was getting.  Nestled deep inside one of the rocks was a crab peering back at me.
<<uh oh>>
I immediately called the girl and asked about this guest in my rocks.  She told me she had emerald crabs in her tank, so it was possible that an emerald scooted in there while she was loading it into a bucket for me.
<<Yes...possible.>>
I quickly looked up emeralds online and found the pictures looked nothing like him.
<<Ah, research...excellent!>>
He is about the size of a half dollar, tan in color with red striping.  Not a thing like the green critters shown!
<<No...and likely a menace rather than not.>>
I called her back and said "are you SURE that he isn't something else?"  She told me that she got the rock directly from the reef, so it is possible that something hitchhiked in on it that she was not aware of.
<<Mmm...obviously something "did"...>>
Here is the problem...I'm setting this tank up for seahorses, and an aggressive crab species would not mix, as you know!  If he were an emerald, which I don't think he is, that might be alright but I cannot risk a mystery crab injuring, maiming or killing my future horses!
<<Even an Emerald Crab would be dangerous, and I would definitely not leave this critter in a tank with seahorses.>>
Any ideas how to get the little bugger out?  I've heard soaking in freshwater will make him vacate.  Is that safe for the live rock?
<<no>>
for him?
<<probably not>>
Any suggestions for me?  All advice is very appreciated.
<<Couple ideas... Remove the rock harboring the crab to a bucket with some tank water...drop in a piece of table shrimp as far from the rock as possible...cover the bucket to block light...if all goes well, the crab will leave the rock for the shrimp so that when you come back (walk softly to avoid vibration) in about 15 minutes, you can quickly uncover the bucket and snatch the rock out before the crab can retreat back to its hole.  Another option is to sink a glass container in the substrate of the tank containing the rock and bait with shrimp.  Usually...once the crab enters the container for the shrimp, it will have enough difficulty scaling the smooth sides of the glass as to give you enough time to capture.  If both these fail, your only option may be to permanently remove the rock (with crab) from the system.>>
Thank you very much for your time (on behalf of me and everyone who picks your brain without saying thanks!)
<<So...that's what that tickling sensation is...>>
Tina
<<Regards, EricR>>