Valonia and Mithrax (3/13/04)
  Greetings and a huge thanks to all you in the crew for providing me and others such invaluable guidance, in the year I've been reading the posts daily, my tanks are UNBELIEVABLE!! Everything is growing and thriving at exponential rates. <Good to hear.> Which brings me to my question. I am getting a ton of green bubbles popping up all over the live rock in my 40 gal reef. I know nutrient control is the issue, and I've greatly cut back my feedings, tweaked my Remora for optimal skimming, and do 2 gallon water changes twice a week religiously. I have been hearing more negative than positive comments lately about Mithrax crabs being destructive and difficult at best to remove when larger, so I'm hesitant at putting one (or any crab) in my system. <Wise to be cautious.>
  Additionally, it seems to be the general consensus that in trying to remove Valonia (various species) one has to be very careful not to puncture the "bubble" so as to not release spores into the water column. My question is: if I do put a Mithrax crab in, isn't that exactly what they do, puncture the algae, and consume it (if they have a liking for it) so why does it not spread under these circumstances? <Some risk I suppose, but does seem to work for some.>
What are your thoughts on just slicing the bubbles open as soon as I see them appear (i.e. real small) with a razor blade? <Vacuuming them off would probably do better. Anthony & Bob's book (Reef Invertebrates) recommends attaching a toothbrush to the end of the siphon. That way you can suck up spores as the bubble bursts. Another option would be to remove rocks that are heavily infested and scrub all the Valonia off in a bucket of saltwater before returning the rock to the tank.> Doing this persistently, would the situation get worse, or better, not allowing any to reach a size greater than 1/8th inch? <I would worry a bit about making it spread more. Your nutrient control approach is vitally important to successfully controlling this algae.> I was thinking doing this, the skimmer and other inhabitants would consume/remove any spores that may get released.. <Will help to some degree.>
  Other than that my tank is looking awesome, and in less than 3 months running, the ENTIRE back face of the tank is totally encrusted in what appears to be at least 4 colors of coralline algae, and the fauna is exploding! ((I chose not to add any fish until 6 mo. to a year) <Your patience will be richly rewarded. Keep up the good work. Choose your fish carefully and quarantine them.>
Thanks again for all you've done to assist! keep up the good work.
Blair <A pleasure. Hope this helps.>

-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>

Crab question
I've got a question regarding Schizophrys dama (decorator crab). about how many species are in this genus,
<this genus of the family Majidae, the Sea Toads, has at least a dozen described species, but several more undescribed as yet... and some majids are not "decorator crabs" per se... and other families contain "decorator" types...>
and are they all in the same genus because they 'decorate', or is it for other reasons. 
<Other, morphological reasons>
I started a 125g reef tank about 5 months ago and am going for a semi regionally accurate system going from the south of the barrier reef to a bit west of Australia (Christmas island). the furthest east ill go is Fiji, and the furthest north ill go is southern Indonesia.
<Like the way you put this>
anyways, I think the whole idea of decorator crabs is pretty cool and am trying to find out some information about them. are their any species that fit in that region that you can think of?
perhaps some or the kind that use anemones as their main defense system? perhaps boxer crabs? any help would be neat
<Best way to approach this IMO/E is to select for the animals on the basis of where they were actually collected... Schizophrys are not "reef safe" as the case with most all crabs... Do look into "The Modern Coral Reef Aquarium, volume 3" here... for about the most up-to-date, complete coverage of potential decapod additions. Sven and Alf's website link can be found on the WWM sites Link Pages.>
Jon Trowbridge
oh, I've seen some online places that sell anemone decorators and am wondering s they sell the baby anemones on them, do they (anemones) usually end up living? or would I get a bag with a crab and a lot of goo....
<The associated anemones live/ship about as well as their hosts... both generally arrive in good condition. Bob Fenner>

The Price of Getting Crabs
Hi guys, back again! I love talking to you people!
<we love you too, dear>
As you may have guessed from past e-mails, I am in need of many things for my reef tank. New Skimmer, more LR, more sand, etc. But I just realized there is another thing I am lacking in my reef environment, sand sifters, crabs, snails. I remember reading AND hearing that these little inverts are about the most important part of a reef,  next to LR. Is this so?
<They are extremely important to the overall health of your sand bed.>
I only have about 15 or so snails, nothing else since my wild caught crabs all died. Which also leads me to this question: Can you guys recommend a site where I can purchase on line? I went to many of the links on your web page Rob, but after about 35 minutes of clicking here and there, I decided to just go to the experts! I will say that I went to WWW.GARF.ORG and they had what appears to be a pretty good deal compare to the $3.99 a piece  price tag at my local shop for crabs, they had a price of about $1.00 a piece for an assortment of crabs and snails. Of course I would hope that these inverts are very healthy and of good size. Can you do better??
<I have heard good things about the detritivore kits from http://www.inlandaquatics.com/  This should inoculate your sand with a nice variety of sand sifting creatures.  -Steven Pro>
Let me know what you all think, and thank you very much for your speedy help as always! Pam