Decorator crab... something growing on it... no pic... Uhhh?  3/23/07
I have read up about as much as my brain can absorb,
<Mmm, may I be excused, my brain is full?>
but I have something on the back of my decorator crab, other than the many things that looks like he put on its back purposely and can not identify. It has spread from maybe a small percentage of the crab's body to about a third over a period of 5 to 6 weeks.
<A fast grower!>
It is clear to white in color with very small specks of bright orange.
<Hmm, maybe a sponge?>
I don't know if it is a disease or maybe even a flatworm.
<Unlikely, I think.>
It doesn't seem to  bother the crab, but it is getting closer to the crab's eyes and  mouth.
<Hopefully, the crab will be able to prevent this from being a problem.>
Any info would very helpful.
<Can't really tell you much without a photo.>
Sorry I couldn't send an image, if I can find a camera with close enough lenses I will send you a pic.  
<Check to see if your camera has a macro setting, looks like a small flower, will allow you to take close ups.>
Thanks,
<Welcome -Mich>
Jeremy

Camposcia retusa... decorator crab, comp.     2/16/07
Hi Crew
<Angel>
I have a question regarding the above.  I have bought one, I suppose it was a bit of an impulse buy as I wasn't planning on getting one,
<Mmm, you're learning...>
I'd never heard of one, but I saw it and was fascinated.  The shop didn't give me the Latin name but from pictures I have seen on the internet it is definitely this one.  It is approximately 10 cm in diameter from tip of leg to tip of leg.
<Yikes... Giganto!>
So he is fairly large compared to my other shrimp and hermits.
So basically I have a tank set up with fish, shrimp (dancing) and hermits (red ones) waiting for my new and improved 700 L new Christmas present tank to cycle.
<Wow! Send your Santa my way!>
It is a reef set up in that I have live rock in it, 2 types of algae plants, under tank sump, skimmer (thinking of getting an ozonizer to make the water crystal, but that is another question for the future may be).  Any way as I have told Bob F in a past email, my LFS only gets small stocks of marine life and quarantines them for about 6 weeks before selling them and I am very good friends with him and the manager and know that all their stock is disease and parasite free.
<Mmm, just my usual cautionary note here re... Most all stores, wholesalers even... can't actually promise such... there is just too much going on... mixed nets, containers, staff... to warrant that contamination hasn't occurred, that new livestock coming/going haven't passed things on...>
So I took the crab home and very excitedly put it (Kev) straight into the new tank (acclimatizing obviously).  Kev is doing really well, but now that I have seen him trundling around and realized how big he is, although small claws,
<...>
I am worried about what damage he may do to my fish and hermits when I put them in.  My LFS friend said watch with small fish and shrimp, but now I am worried what would be classed as small relative to his size and eating habits.
<Ah, yes>
  My smallest fish at the minute is a young clown who is approximately 5 cm.   So at the moment I am holding back on transferring my buddies into the new tank.  
<You are wise here>
I know that in the aquarium world you cannot be certain of anything, but I thought you probably know more about their track record for compatibility than most.  On a positive note though the Caulerpa sp. I bought had some hitchhiker xenia on it and so I have attached this to the rock and he hasn't demolished it and only took a little, so maybe Kev is the caring type.
<Or not caring for Pulsing Soft Corals... as the present "menu item">
   Have had no replies on the chat forums so its over to you!  
Thanks in advance Angela (WWM fan).
Please let Bob know that his book CMA is brill!!  
<Much good help with this tome. I would definitely keep your eye on Kev... and a spot in a refugium to move it/him too not if, but when he becomes too much of a tankmate sampler. Bob Fenner>

Re: Camposcia retusa comp.    02/17/07
Hi Bob
<Am everting my lips in my best... well... semi-okay impersonation of MickJ... "Angie...">
Thanks for the swift reply.
<Welcome>
Would you say he is probably too big for the rest of my fish and crabs who are in shells of about 4 cm?  Give it to me straight, don't spare my feelings!
My largest fishes are:
12 cm blue Cheeked goby
12 cm long Midas blenny
8 cm long Regal Tang
I know that I can return him, sad though I would be.  But I don't want to
be unfair to my other fish friends.
<Mmm... if it t'were me, I would return this Decorator... Too likely to be heartbreaks down the line>
What do you mean by "Much good help with this one tome."
<Oh, the publisher, James Lawrence is a pet-fish and publishing genius... a delight to work with him and the Microcosm crew>
Angela in a dilemma.
<BobF, in a heat to get out and work on the garden walk/run the dogs...>

Re: Camposcia retusa comp.    02/17/07
Thanks for that, he will be going back to the shop tomorrow, but he will be in good hands.
<Ah, good>
From Angela (named after Carly Simons "Angie baby").
Night time here so off to bed.
Good night from rainy Manchester..
<Sleep tight... from nice/sunny (today) southern California. BobF>

Sponge Crab Questions (4/16/04) 
I have a 1 1/2 inch sponge crab that I am keeping in a 20L aquarium right now with a few fish..... I call him "Sponge Bob." Bob is a cute little fellow but I know very little about his dietary requirements. He is eating small pieces of silver side right now. What else would give him a good balanced diet? I assume, like most crabs he is not reef safe, right? <Exceedingly unsafe and very destructive.> I would love to put him in my Harlequin Shrimp tank ( it has a few limpets too) but fear he might hurt them, would he? <Quoting Calfo & Fenner, they "have no place with a casual marine aquarist or in mixed invertebrate reef aquariums.> He lost his sponge and is currently carrying around a small piece of green 3M brillo pad on his back........I call him "Brillo Bob," now:) Thanks for the help! Janey <These crabs do tend to be omnivorous with a leaning toward meaty foods. I had a hard time finding much info. I'd suggest you search the terms "sponge crab" and "Dromid" on WWM & Google to get more info. Steve Allen.>

Decorator Crab Woes [Not A Question; More Of An FYI]  - 04/26/06
Hi Gang, <Hey there>   
I had an unfortunate event yesterday with a decorator crab that I wanted to share in case anyone else is considering getting one of these creatures.  
<Share away, we love this stuff!>   
My partner and I have had our aquarium for about two months now and are having a great time with it.  
<Wonderful!>
We're very pleased with it's results and with our damsels.  We made the decision over the weekend after positive tests that it was time to increase our stock from two damsels to a couple of shrimp, a crab and a Nudibranch.  
<Be very wary with the last.  These do not survive so well in captivity.  Most times they perish fairly quickly.>
So we set off to the pet store and in our ventures wound up getting a starfish, a decorator crab, two cleaner shrimp, a blood shrimp and a Nudibranch.  All was right with the world.   
We got them home; floated them
<Tell you the truth, you should float them, but drip acclimate them.>
and put them in the tank still under the illusion that everything was great.  With amazing speed (which tends to happen in this hobby I've found) everything went horribly, horribly wrong.  Our tank is a forty-five gallon bow-front with 15 pounds of live rock, a three inch live sand substrate and giant piece of dead coral to provide hiding places.  With the rocks and the coral, there are a ton of places for the guys to hide.  As we expected, the decorator crab started off nice and leisurely picking up stuff from the tank as we were expecting him to do.  When he came across the blood shrimp, which had perched itself on top of one of our live rocks, he apparently didn't like him there and quite simply attacked him.  The blood shrimp having a brain the size of, well, a shrimp tried to fend his territory.  
<Ha! This isn’t uncommon though.>
You can guess which one won.  The shrimp lost half of one leg on one side and one whole other leg from the other side .
<Oh boy, probably tasty, but an expensive snack.>
The decorator proceeded to make fast food of this delicious new meal and go back for seconds.  He started actively pursuing the blood shrimp.  Right before a second confrontation, during which I'm sure the crab would have killed the shrimp, I finally took the blood shrimp our of harms way and perched him on top of the coral where I though he would be out of the reach of the decorator crab.  Once again, all seemed well.   
Concerned about the crabs aggressive behaviour (we'd gotten mixed reviews on this aspect of the decorator crab during our research); we decided to keep an eye on him for a bit after lights out.  While we were observing the tank; we noticed that the decorator crab had turned his attentions to the cleaner shrimp and was actively pursuing them; stalking, we're almost certain, with intent to kill.  Fortunately, they were small enough and fast enough to evade his reach.  Satisfied that he at least wouldn't decimate the rest of the aquarium, we made the decision to call it a night and started debating taking him back to the pet store the next morning.
   Sometime during the night he managed to get to the blood shrimp again; this time dealing a fatal blow.  
<Oh no!>
The shrimps carapace was split down close to it's tail, two more legs were missing and one of his feeler antennae had been ripped in half.  He died shortly after we found him like that.  At that point we were pretty upset because we loved the shrimp (he was absolutely beautiful) and because he had cost us twenty dollars.  Where we were only debating returning the decorator, we made the decision at that point.  We figured it would only be a matter of time before he got his hands on the Nudibranch, the cleaners or the starfish (all of which had cost a grand total of $130.00).   
I'm writing this to get the information out there if you guys see fit to publish it.  
<Absolutely!>
The research we did on the net was mixed with regard to aggressiveness of this species; although it tended towards them being relatively easy to keep and working well with other animals (possibly with the exception of SLOW moving inverts - I don't consider shrimp slow-moving but could be wrong about that).  
<Sometimes they just have different personalities.  Info here or anywhere is based on the majority of cases, sometimes it may be different because each specimen is different.>
Our experience says something very different.  This particular crab was extremely territorial and aggressive to the point he was actually hunting his tank mates.  It doesn't seem like a good choice in an aquarium where other crustaceans are housed.
 We've since replaced him with a few snails and feel much better for the wear.
<Great idea!>  
Thanks for putting this out there for your readers and for the great work you guys continue to do at WWM.
<No problem, best of luck in the future, Jen S.>  
Warm regards,
Dennis

Decorator arrow crab-
Hello
I have an interested in getting a Decorator Arrow Crab <Hmmm, I'll assume Camposcia retusa?>, however I have heard they can be troublesome to other animals. <Mainly with sessile inverts that easily become body ornaments.> I have the following in my fish only tanks.
1 Blue Moon Angel
1 Yellow Tang
1 Starcki damsel
4 young Clownfish
2 Emerald crabs
4 Urchins
2 Serpent Stars
1 Orange Starfish
about 15 Small Hermits
About 20 snails
2 Blood Red Shrimp
My tank is a 210 Gallon with 180 lbs of rock.
Do you see any problem adding this Crab? <These guys are opportunistic carnivores, but shouldn't seek out and kill fellow tankmates. If what you are referring to is Stenorhynchus seticornis, then there is an added threat to tube worms and it can pick on just about anything. This one is the true arrow crab, but not a decorator. I hope this helps! -Kevin>
Thank you for your time.
Kurt

Re: Decorator crab
Would you also approve my tolerance of a small decorator crab?  True he tears up some polyps and zoos from time to time, but I think that's good for the tank since the polyps and zoos end up getting seeded in other spots, plus the crab is kind of interesting.
<You have my endorsement here. Perhaps you will help our species in self-governance one day... and soon I hope. Bob Fenner>