Coral Attack, Zoas vs. Decapods  9/16/09
Need more help.
<I know I do>
I have a 135 with 150lbs of live rock. Nice and purple. Nitrate is less than 10 and on its way down, as I just installed a RDSB. I found a single Zoanthid growing on the rock and figured it was a good time to put a few test corals in. I put in a small frag with about 10 Zoanthids. The Zoa's were attached to the skeletal remains of something. It was not a rock. The first night one of the hitchhiker crabs apparently removed the coral from their attachment and took the structure away.
<Wow; strong crabs>
I found the Zoa's on the bottom curled into a ball. I have replaced them in another location and they are slowly moving up the rock.
Is any of this normal? Will the Zoa's recover?
<Mmm, hopefully. You might want to rig some sort of strong cover over them for now. Maybe a plastic "berry" container, inverted, tied down with all-plastic ties.>
I have seen 3 crabs. Based on their claw configurations, 2 need to go.
The last time I tried trapping, nothing happened. I assume crabs do not hunt during molting?
<For the most part this is so>
I found sheds during the time I tried the trap.
I really appreciate all the great information on the site and in the Bob's books. The entire family is having a great time learning and watching new things happen every day.
<Ahh, great! BobF>
Thanks,
Erik C. Hayes

Decorator Crab; Feeding And Compatibility 8/30/09
Okay, so my roomy and I recently set up a 25 gallon salt water aquarium consisting of crushed coral and about 8 lbs of live rock. We decided to throw in a Spider Decorator Crab to entertain us while we
wait for the tank to finish curing and ammonia levels to get as close as possible to zero :) (we made sure they were pretty darn close to nil before adding the crab).
Squeegee, as we named him, seems pretty content, scavenging the tank for whatever he can find on the live rock, not-to-mention the assortment of tropical flakes that we throw in on a day-to-day basis.
This leads me to my first question. Are the flakes enough for the crab to eat and if so how many should I be throwing in there? Also, would feeding the crab ghost shrimp be okay (if so how many a night)?
<Ghost shrimp are fine, maybe one every other day depending on the crab's size. Kind of pricey for crab food.>
And lastly, Is there a more ideal (and cheap?!) sustenance we could be feeding it?
<Flakes are fine and about as cheap as you can get. A few flakes per day should keep him happy. Crabs are opportunistic scavengers and will eat most anything they can find.>
Finally, as far as compatibility goes... the tank was originally intended for a Snowflake Eel (no fish) which we'll be getting as soon as the tank is ready. Do you think a young (6in) Snowflake would attack/devour Squeegee?
<A excellent chance for this to happen as crabs and shrimp are their main diet in nature. Do be aware that your tank will eventually be too small for keeping a Snowflake Moray in good health.>
Would there be any way that we can get them accustomed to each other with adequate feeding long enough so that they can coexist for some extended period of time?
<No. Do read here. http://www.wetwebmedia.com/snowflakemoray.htm>
Thank you!
<You're welcome. James (Salty Dog)>

Black Mithrax Crab HH, incomp.   8/7/09
Good morning crew,
<Hi Jessy here>
I have a few questions about a hitchhiker. I've actually been trying to catch it for a month or so, but I've never had any problems with it until now. I have identified it as a black Mithrax crab. it looks and feeds like
an emerald but black with very hairy legs. (That's kind of a "duh" statement isn't it?) I recently had a pistol shrimp and a black ray goby pair up and make a burrow underneath my live rock. I came home one day to
find the shrimp gone and his goby hiding. Later the goby abandoned the burrow and the black Mithrax emerged from their den. The next day the goby returned for a while, and that was the last I saw of him again. The Mithrax isn't bigger than the goby, but could he have eaten them both?? I would think the goby would have protected his buddy, but maybe I'm confused. If this crab did kill them both, how do I trap the SOB?
<Jake, unfortunately that is probably exactly what happened to your poor pair. Those little devils of a crab are bad. To trap them, I've heard many things. They are much like mantis shrimp...hard to catch. I've heard of everything from a small glass jar being buried neck up in the sand for the crab to crawl into with food as bait, but not be able to get back out of.
I've heard of outright spearing the little buggers, but that seems a bit extreme and skilled. The last way I can suggest is figuring out what rock the little guy stays in and removing that rock from the reef to be flushed
out in fresh water or prodded until you can better see the culprit. Either way, it is not going to be an easy process. I wish you luck!>
Thanks,
Jake Maenius
<Regards, Jessy>

Zoanthids Disappearing, Hitchhiking Crabs – 7/18/09 <Hello Jared, Lynn here this afternoon.> I have been loosing the expensive Zoas fairly fast each night. <Yikes! Have you looked for the usual suspects? Please see the following links for more information/photos: http://www.zoaid.com/gallery2/main.php?g2_itemId=384 http://www.zoaid.com/index.php?name=FAQ&id_cat=3#q15 http://www.wetwebmedia.com/zoanthidcompfaqs.htm > The ugly cheap ones are doing great just like kudzu (of course). <Murphy’s law strikes again.> I have lost a quite a few whole colonies of tubs blues, gorilla nipples, fire and ice, black cherry and so on. In all about $300 of Zoas!!!! <Yowza!> I pulled out my trusty red lens light 3 nights in a row and found this guy in a hole near the Zoas. Now I do not know if he is the culprit, as he does not have the really fuzzy bear legs or sharp claws on the ends (they are flat and look just like a emerald crab)....so a rogue algae eater gone to the dark side maybe???? <I don’t think the crab was actually eating the Zoanthids, but it’s possible that his presence was acting as an irritant. In which case, you’d have noticed the polyps remaining closed for extended periods of time (not disappearing overnight). I guess it’s always possible that, for whatever reason, the crab was pulling the polyps off the rock. I just don’t know. What you describe sounds more like deliberate predation. I’d look for Nudibranchs, Heliacus/sundial snails, and others listed at the above link. One other thing to do though is check the remaining Zoanthids for any sign of small light/whitish spots. If so, it could be what some hobbyists call Zoanthid pox. Please see this link for a photo example: http://www.zoaid.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=3573 For treatment, see first FAQ, titled “Zoa Pox Treatment – 05/09/09” at this link: http://www.wetwebmedia.com/furancpdfaqs.htm More info here regarding diagnosis/treatment: http://www.wetwebmedia.com/zoanthidhlthfaqs.htm > Plus he lost a leg battling me. <Oops!> I accidentally skewered it with a bamboo skewer and was able to force him out of the hole that way. I have him in my fuge with easy access to remove him, but I have found 2 more EXACTLY like him in another piece of base rock. And of course they are either too far in or they scurry away before I can get them. <No kidding. They know they can’t win a battle against the skewer-man!> Zero damage as of yet from them, but I am still trying to get them. <I would do the same.> He looks very similar to the header pic and last pic on: http://www.wetwebmedia.com/Arthropoda/CrustaceanPIX/SWCrabs/Crab%20IDs/swcrabid12.htm <Gotcha. Although those claw tips look fairly blunt, they don’t appear fully spatulate like those of emerald/Mithraculus crabs. Also, the presence of hefty molar-like (“molariform”) structures on the inside edges indicate that the claws are less adapted for eating algae and more adapted for crushing – usually mollusks. Crabs on the whole are omnivorous creatures. They’re usually okay in reef tanks when small, but can be a problem as they grow larger.> What do you guys think????-- Trigger/octopus food or not? <Well, the trigger and octopus would definitely love it, but I’m a softie; I’d spare their lives and find them a new home in the sump or elsewhere.> Jared <Take care, LynnZ>

Crab stow away and dead shrimp/snails   5/1/09
Hi
<Hello>
We are new to your site and hope that you can help us. We have a 30 gallon marine tank and just discovered that we had a stow away crab. We assume it was in the live rock. We found two claws and a top shell that was about 1" and 1 1/2" across which was white with brown spots. The crab type really doesn't matter as we have lost 2 peppermint shrimp, 1 fire shrimp, and about 20 snails in the past month, so we hope to get it out of the tank.
The thing is, my husband moved our fish to a quarantine tank (hopefully to save them from becoming dinner, and he removed all of the sand as well to a couple bowls trying to shift to find the crab. He didn't find a crab but he did find 3-4 solid white mucus chunks with a few black lines in it. The chunks were about 1/2" each. Could this possibly be the remains of the crab if he squished it?
<Possibly, but he is probably hiding>
Last night we saw the first claw so we think it must have just lost it's shell. We want to know if we have accidentally taken care of the crab (by squishing him) or if he is most likely hiding in the rock. Needless to say we don't want to keep feeding him our daughters fish for dinner.
<A trap might be your best bet. Commercially available traps are normally pricey, but you can actually make one yourself by burying a glass jar in your sand bed and baiting it. The best time to do this is likely at night, the crab should go for the food and then have difficulty climbing out of the smooth jar.>
<I suggest reading here
http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/swcrabfaqs2.htm
>
Thanks,
Tami & Mark
<Your Welcome
Josh Solomon>

Decorator crabs. Comp.  04/03/09
Hi, i have 2 decorator crabs in one 30 gallon tank, they were fine when i brought them home a few weeks ago and were small. Once they got a little bit bigger it seems they try to eat everything.
<What they do>
I have never dealt with this type of decorator. It's the sponge decorator variety of crab.
<There's more than one species...>
Should i get rid of both or just one?
<... what do you want to have else-wise?>
I planned on getting a different species that i have had experience with but not this one. I was given these two when i ordered a different type of decorator.
<Mmm, I'd likely trade both in... you will have "issues" with one, two... in any case. Bob Fenner> 

Need to rid my reef tank of an Emerald Crab! A Suggestion   3/23/09
Hello,
<Hi there James, Mich with you.>
Great site by the way.
<Glad you like it!>
I made a terrible mistake and put two emerald crabs in my reef tank. Why a LFS would sell these things is beyond me
<They have their uses I suppose. But I personally am not a fan.>
but I was dumb enough to buy two, not one! I have found out the hard way that these crabs only eat coralline algae off of live rock, or better yet, coral polyps, and this is also based on other reefer's experiences with these crabs on other blogs. I tried your raw fish in a jar trap and the male went for it after a few hours and I got him out (yea).
<Yay!>
The female crab will not go for anything even if its a few inches away and stinks really bad!
<Heehee! Perhaps the females of the species are smarter than the males?>
Is there any other way to get this miserable creature out of my tank if raw meat doesn't work?
<Well I don have a suggestion but I'm not sure you'll like it.>
I think I would rather pour bleach in my tank
<PBITAWA???>
and deal with that than watch this thing eat every polyp off my corals, oh yea, and my coralline.
<Well here's my trick. It sounds like you know where she lives. You need to remove that rock. Take that rock and put it in a long under-the-bed type plastic storage container filled about a quarter of the way with water. Elevate one side of the container and put the rock in the area that is the deepest. Then gradually over the course of say 2 hours or so move that rock higher up the incline so the rock is in ever more shallow water.
Make sure you put some PVC or some small rubble in the deep end of the water so the crab has some place to hide. But the crab in my experience will want to stay in the water and you will likely find her hiding in the safety of the hiding places of the deep end. I know you are probably not very fond of her right now. But please, this animal is doing what she has evolved to do, have mercy on her, care for her responsibly, move her to your sump, return her to your LFS or find someone who can provide her the care she needs.>
My tank is a RedSea Max 250 (65 gallons). Thanks for all your great support.
<I hope this helps!>
James
<Mich>

Good crab or bad crab?? 01/22/09 Hello Crew, I have several. Purchased from a fellow hobbyist as reef safe. He said that they are emerald crabs, but they are more Tan with dark green pigment than all dark green. <One of the troubles with common names... there are several species of Mithrax crabs that sometimes get lumped under the common name "emerald crabs." The green ones are the Mithrax sculptus. But there are other species which look a lot like M. sculptus, but that are more red or brown (some are even black).> I have had them for a few months with no damage, but I realize that I am not sure what they are, <Possibly M. forceps... but it's very hard to make much out in the photo.> which is a bit unnerving. (Yes, I should have been more considerate before adding them)/ The claws are light. If they are in fact bad, what is the best way to remove/catch them. <No crab is 100% reef safe. But the Mithrax crabs tend to behave themselves more than most when they're well-fed. They are good scavengers and algae pickers. I wouldn't remove them unless they start to become a problem (i.e. just keep an eye on them).> P.S. Pic is in the worst corner of the tank. Ignore the Kenya tree and Aiptasia please. Thanks very much, Mitch <De nada, Sara M.>

SW Crab Question, incomp.  – 01/13/09
Evening crew, from snow buried Chicago!
<<Greetings Heather… From a somewhat more pleasant South Carolina>>
A few weeks ago while gazing at my tank, I discovered a new (well, not quite new, but now large enough to be noticed) inhabitant, a crab.
<<Mmm…>>
From the searching I've done with Google on WWM, the closest comparison I could find was the Banded Clinging Crab, Mithrax cinctimanus, but that is a rough comparison.
<<Okay>>
My crab is now about the size of a dollar coin, roughly an inch wide body. It is a dark brown/black base with orange markings or "patches". My tank is a 55 gallon with live rock, a Royal Gramma, two Ocellaris Clowns, two Skunk Cleaners, and five Peppermint Shrimp. The Peppermints have only been in the tank for two weeks. I did a head count last night (somewhat difficult to do with 60lbs of live rock...) and all are still present. I was wondering if I should be concerned about my newly discovered crab harming any of my other inhabitants, mainly the shrimp?
<<Very possibly, yes…and the fish too. Even if this is a species of supposedly “reef safe” Mithrax crab, large specimens are known to pose a hazard re. If this is not a Mithrax species, the concern/hazard is likely even greater as this crab continues to grow>>
If it does pose a threat, how is best to remove him?
<<This can prove difficult… A trap of some kind… Perhaps a small jar baited with a piece of meat of marine origin placed in the sand or among the rock. Do also peruse WWM re “crustacean removal” for other’s thoughts/ideas>>
It seems to us that he has grown since discovering him, so my hopes of him not getting any bigger are gone.
<<Indeed>>
Thanks much for everything you guys do! Mr. Fenner's book is one of my most read!
-Heather
<<Happy to share, Heather. Good luck with trapping that crab. EricR>>

Crab eating open brain?? 01/04/09 Hi there! <Hi> I have been spending a lot of time on your site and it has helped me tons! I have also listened to Bob (just bought your conscientious book) Bluezoo Radio which I listen to and love! I have a question I needed to write in for... I have a 29g mini- reef, running now for 3mos. Ph 8.2, 78 degrees. N , No2, and No3 all 0. Ca 380, KH 8. I am running a Current Satellite 30" 60w SunPaq dual daylight, dual actinic, w/moon for lighting. I am also using a hob filter using foam, and carbon, an AquaC remora skimmer, both hung on the back of tank, and 2 powerheads placed in the top front corners of the tank pointed to the opposite lower back corners of the tank. My tankmates are: 1 turbo, 1 Trochus, 1 emerald crab, 1 peppermint shrimp, 1 blue knuckle hermit, and around 8 mini hermits. I have a few small Seastars that hitchhiked into my tank as well. I acquired 2 colonies of Zoanthids, a sponge, some tube (feather dusters?) worms, and some mushrooms on my live rock. The corals I purchased, were acquired from the same LFS; Euphyllia Frogspawn, Dendrophyllia (my favorite) , Caulastrea Candycane, Xenia, Nephthea, Diaseris, and a Trachyphyllia g. (pink and green). All seem to be doing great, (with the exception of my Trach, which brings me to write to you) expanding fully and eating. <This is a lot of different types of corals for such a small tank. I would expect some chemical warfare problems... if not now, then in the near future.> My question is about my open brain. He's been in my tank about 5 weeks . I originally had him up on a rock, just an inch above the sand, but my pesky blue knuckle hermit kept mowing him over into the sand, along with everyone else! I have since used Aquastik to glue all my corals to the live rock, and put my brain onto the sand as I've read is better on your site. <Ah, good.> He seemed to settle in, expanding during the day, after having what seemed to be a tough few days. He did still eat a small mash of raw shrimp 3 days ago. I tried to feed him yesterday, and a puff of brown 'smoke' came out of one of his mouths. Good/bad?? <It is likely expelling waste (maybe even expelling zooxanthellae-- judging from how it looks a little pale, this could be "bad").> Tonight, after my actinic lights shut off, I found my Blue knuckle hermit on the edge of my open brain. The hermit looked like it was shoving his legs and claws into the edge where the pink outside, meets the green inner side (where the brains mouths are) kneading it like a cat. I tried to move it away from my brain , but it grabbed hold, and wouldn't let go. I tried luring it off my brain with a piece of krill, but it was more interested in pawing at my brain for a bit longer until the brain was totally drawn into its skeleton. It finally lost interest and moved on . Was my Hermit eating my Open Brain coral?? <This is a bad sign. Hermits are mostly opportunistic eaters. It was likely either trying to steal food from the coral, or picking at weak tissue.> Is my Trach dying? Should I remove my Hermit? <Possibly, unfortunately-- but the good news is that it's far from dead just yet. Yes, I would remove the hermit and target feed the coral.> 2 last questions; What other corals do you think would be a compatible next purchase to go with the corals I already have? I would love to buy 3 or 4 fish. Any suggestions?? <IMO, you have too many different types of corals already. As for fish... keep them small and few, gobies, chromis, maybe Perculas... please read, research thoroughly before purchasing.> I have attached a picture of my Trach that I took just yesterday, and a pic of where things are set up in my tank. Thanks for taking the time to answer my questions!! <Good luck> - Nancy <Best, Sara M.>

Hitchhiker Crab and Dwarf Morays, comp.s 12/02/08
Hello,
<Hi Paul.>
I recently ordered two Gymnothorax melatremus (Golden Dwarf Moray) and plan on putting at least one of them in an established 58 US gallon reef aquarium. Would it be advisable to put both eels in the same aquarium as they are not actually a mated pair?
<Preferable, sometimes found as pairs in nature. Your two may become a pair and should only be separated if they start to fight severely, which is less probable even if they have the same gender.>
If not I can place them in separate tanks easily.
<I'd leave this option if fights should start. In this case one will more easily be caught with net.>
My second question concerns a Xanthid crab that I recently found in the 58 gallon reef. More specifically, I found a molted carapace approximately one inch across along with claws and other bits of old crab exoskeleton. Will this crab pose a danger to the eel(s) if I put them in the tank before I can capture the crab?
<If the eels are at least 6" they should rather be a danger to the crab. If they are significantly smaller I'd catch the crab with a crab trap just for peace of mind.>
I already believe he has killed fish in the tank as a pair of Banggai cardinals went completely missing several months ago. I did read somewhere that golden dwarf morays would eat invertebrates, but would one be able to take down a crab of this size?
<Depends on their size, physical condition, crabs are their favourite food. Healthy specimens of 6" should be safe, only dead/dying small eels (this reclusive and expensive species is sometimes caught with poison) may become crab food. I've seen relatively small morays tearing off pinchers of crabs they could not eat as a whole. They are able to tie a knot into their body and pull their head and the prey item through the knot.>
In any case the morays will go into a quarantine tank, at least until I hear back from you.
<Okay.>
Many thanks, Paul.
<Welcome. Marco.>

An answer, rather than a question! Crab eating SPS 09/18/2008 <<Good day, Bob, Andrew today>> I see a lot of posts asking about crabs. Here area couple of very good pictures of one that I guarantee is an SPS-eater. <<Heeeee...i would certainly agree>> The coral he lived on was getting 'tracks' all over it of nipped out polyps, etc. After he was removed, the coral completely recovered. Feel free to use the pictures as you like. [IMG]http://i226.photobucket.com/albums/dd7/Coralmaker/crab2.jpg[/IMG] [IMG]http://i226.photobucket.com/albums/dd7/Coralmaker/crab1.jpg[/IMG] bob <<Two really great shots there Bob, and they will certainly be welcomed into our picture database. Thank you very much for providing / sharing two wonderful pictures. Kind Regards, A Nixon>>

Pom Poms and Croceas 9/9/08
Hi there guys,
I have a nano 10 gallon with a 175W Metal Halide on it.
<"Giant steps are what you take, walking on the moon/sun">
It has a 2.5 gallon sump/fuge with mangroves growing in it.
14.5 pounds live Rock, 10 Pounds Live sand, assorted sps and LPSs plus Zoos and Palys, Established tank, 9 months old.
Ok, so my question is this. Stinging corals, especially LPSs, can harm clams very easily if they get too close. But can anemones do the same?
<Yes>
More specifically, I want to get a pom pom crab because I think they are very interesting, and
well, just plain cool, but would this Crab hurt my clam. My porcelain crab and my emerald crab both love to climb over
everything and make a mess. Could this be problematic with a pom pom and a clam?
Thanks,
Andrew
<Some chance, but most Lybia avoid the mantles of clams... The real issue here is going to be "just size/volume"... When, not if, "something" goes awry here, there is going to be very little "wiggle room" or reaction time to prevent a complete melt-down. Bob Fenner>

Re: Gaudy clown crab  4/16/08
Thank-you for replying. Today our shipment of live rock arrived of 85 pounds. When we were done placing it all in our aquarium we tried to get the gaudy clown crab out but it was wedged so far into that one rock it didn't make it.
<Sometime later then... baiting, trapping...>
Later on tonight we were looking and in the corner of our eye we noticed a second one. Now is it safe to keep in our aquarium?? Or should we put it in another tank? We have fish and shrimp and blue legged hermit crabs etc. Please reply and let me know thank-you
<Please read here: http://wetwebmedia.com/swcrabcomp.htm
and the linked files in the series above... till you understand your options sufficiently. Cheers, BobF>

Re: Gaudy clown crab  4/16/08
I looked on that site that u
<...>
 gave me there was nothing on there about gaudy clown crabs. Im sorry to be bothering you again its just no one around where I live knows anything about them. I would be grateful if you helped me know more about the gaudy clown crabs.
<... Please read generally re the Compatibility of marine crabs period... B>

Crab Removal and Tuxedo Urchin vs. Soft Coral – 12/13/07
Good morning,
<Hi David!>
I'm curious about the jar method for catching crabs. I took equivalent of a pop bottle, carefully peeled off the label and scraped off any adhesive... Then I boiled the bottle in a pot to sterilize it for 5 min.s. Once cooled down, the bottle was perfectly clean and hopefully sterile. I filled the bottom with about 3" of sand and placed 3 pieces of krill in it... The bottle is leaning up against the crab infested rock...48hrs... No crabs trapped.
<Takes time, patience, right bait, and hungry crab(s).>
The largest crab could fit into the bottle opening sideways. Do you think I'll have better luck if I use more sand to bring the bait closer to the neck of the bottle?
<Can try this, as long as the sand isn’t up high enough to allow the crab to grab the top edge of the bottle and crawl out. One possibility is that the krill just might not be “stinky” enough to lure him/them in. It sure would have been nice had the crab(s) gone the easy way and fallen for the jar trap! Since they haven't, and it sounds like the crabs are all still fairly localized, I'd consider removing the rock to a bare bottom quarantine tank and thus gaining the upper hand. One of the many good things about this is that you can control the food supply. When he/they get hungry enough, they’ll go after whatever’s in that trap. It also eliminates the possibility of your other inverts accidentally wandering in. The main advantage though, is that the crabs can't wander off and take up residence elsewhere in the display before you catch them!>
This morning I spotted the large crab likely about 4" away from the Jawfish. <Hmmmm> The Jawfish didn't seem concerned and the crab was feeding on some Caulerpa. I have had emerald greens before without incident (mind you none were this big)... This crab looks identical to the emerald green Mithrax, except it is black with sandy brown legs. Would you say that any crab that's of decent size is likely risky in a reef tank with smaller fish?
<Yes>
He is kinda neat, but obviously I don't want to stumble upon a Jawfish carcass one morning.
<No kidding!>
If the 'jar method' for catching these critters takes too long... Do you think removing the liverock and placing in a bucket of tank water and putting some powerheads on the holes would drive them out into the bottom of the bucket without damaging the feather dusters and soft corals?
<You could give it a try, but I’m thinking it’s more likely the crab(s) will simply hunker down/go into an area of the rock that’s not getting blasted. There's also a good chance that it could damage those soft corals. My next step would be as stated above: QT, control food, trap/net.>
I have a fairy wrasse in quarantine and I suspect the wrasse will find this crab infested liverock that is so porous with a variety of large chambers within... Of particular interest for a home. Sleeping wrasse in liverock infested with a few small crabs and one brute... Ok, maybe I am answering my own question. Could be disaster?
<Heeee! Yes – something along the lines of “Come into my parlor, said the spider to the fly!”. Depending on the size of the wrasse, you might be able to block off/separate part of the QT with Eggcrate, or similar.>
Lastly, I mentioned my small tuxedo urchin sitting in my soft coral tubular polyps. I believe he was just passing through. You had mentioned I should move him. Anyhow, when I came home from work all the polyps were open and no apparent damage and urchin seemed ok as well. This is two days later now, again last night Urchin was sitting in the polyps again. <Hmmmm> I'm wondering if you figure he's once again just passing through or... Can/does an urchin actually feed on corals?
<According to what I’ve read, Tuxedo urchins/Mespilia globulus, rarely eat corals. They’re mostly herbivorous, but if they ran out of algae/got hungry enough...? I’m a little concerned, about the repeated visits to the soft coral – unless it’s dining on algae on the base/where it’s attached. Would monitor closely for any signs of damage.>
Anything I've read suggests they are totally reef safe. If no damage is being done I'd like to keep both... The alternative is to move the tuxedo urchin to my 200g FOWLR tank that houses a Snowflake Moray, Foxface, Harlequin Tusk, and soon to have tangs/Angel/trigger....
<Would monitor, relocate if necessary.>
David Brynlund
<Take care - Lynn>

Dragonet and Sally Lightfoot Crab 12/1/07
Hello, I love your site and thank you in advance! My question is regarding a Sally Lightfoot Crab and my Dragonet ( a scooter blenny or perhaps a starry blenny). The dragonet is slow moving and just kind of "hops along" the tank and rock work. Will my newly purchased Sally Lightfoot be able to catch him and/or is he a threat to him?
<Yes it can. Although it is not a guarantee that he will.>
I heard from my LFS salesman that my dragonet is poisonous to eat displayed by the bright colors. Is this true and will that deter the Sally Lightfoot?
<They are somewhat thought to be. Do not trust that particular crab (and several others) in with such a small, slow moving fish.>
Thank you
-M. Allebach
<Welcome, Scott V.>

Seahorses and crabs 10/16/07
Hi. I recently purchased a pom pom crab. He is ready to come out of quarantine. I was planning on putting him in my reef tank, although I have a Rolland's damsel that is becoming aggressive and may have just killed my strawberry crab. I witnessed the damsel attack the strawberry crab the other day. The crab got away quickly, but this morning I found him laying dead in the sand and am wondering if the damsel is to blame since the crab seamed otherwise healthy. Plus the new crab is so tiny that I doubt I will ever see him again in a 55 gallon tank.
<Too likely so>
I also have a 20 gallon tank with two young h. erectus. Would it be safe to house the pom pom crab in the seahorse tank?
<Mmm... a better choice than with the Rolland's...>
I know that anemones and seahorses do not mix, but will it matter when they are so tiny? Is there any way the pom pom crab would hurt the seahorses?
Thank you all so much for your help. Your website and helpful expertise are a blessing!
-Connie
<Thank you. I would take the risk here myself with the Seahorses. Bob Fenner>

Random questions/reef tank... maint., crab comp., Zoanthid contr.  9/26/07
Hello all and thanks for the great website! I hope this is not too annoying an e-mail, but I have several somewhat unrelated questions that I hope I did not miss the answer to in the FAQs. We have a 90 gallon reef, 4 inch DSB, 120 pounds live rock, with the following livestock:
Naso tang (N. lituratus),
<This genus, species needs more room than this... as stated on WWM...>
pair of Clarkii clowns, mandarin dragonette, double-barred Rabbitfish, yellow tang, cleaner shrimp, peppermint shrimp, and sally light foot crab. It's the dreaded "garden reef"
<Heee!>
with predominately SPS in the upper third and LPS in the bottom half. However, just to cause trouble, we have three different types of Zoanthids and two types of mushrooms. We have a protein skimmer and run carbon. No new fish or invertebrates have been added in over six months. Thus far, all corals appear to be flourishing and all fish are happily coexisting. Don't panic over the stocking..... we are in the process of upgrading to a 220. The tank is finally in and husband is installing the floor jacks tonight! Parameters are:
ammonia/nitrate/nitrite/phosphate-0, SG-1.025, pH-8.1, temperature-81, calcium-450 mg/dl, and alkalinity-8.5 dKH.
So, on to the myriad of questions......1. The Rabbitfish has developed a pink hue on both lateral sides just dorsal to his abdominal area. I have not seen this in any picture of a Rabbitfish, but perhaps it's just too subtle for pictures. Is this something to be concerned about?
<Mmm, yes... highly likely environmental/stress caused... will abate with the move to larger, better setting>
Fish is eating fine (varied diet of Mysis and other frozen seafoods, Nori, flake, pellets, etc.) and acting the same as always.
2. I inquired about a final fish to the stocking plan and EricR had suggested a powder brown tang. We weren't crazy about the tang when we looked, so what are your thoughts on a Sargassum triggerfish? Do you think the odds are good that this would be a reef safe fish (no guarantees we realize) and that this an appropriate addition to a peaceful tank?
<Are good animals for larger systems... and not too adventitious as other Balistids... May still sample your cnidarians>
3. The yellow Zoanthids (Parazoanthus gracilis I think) have gone absolutely out of control. We started out with a small rock with perhaps 5 polyps on it over a year ago and we know have hundreds of polyps. They have grown through the rock to come out in different areas.
<... got to keep them isolated... on their own patch of rock...>
When we try to prune them, one polyp always seems to escape and then a new colony starts wherever it lands! They are growing across the sand bed, in the back of the tank, and even in the middle of other Zoanthid colonies. Any suggestions for curbing their growth?
<Remove as much as you can in the move to the larger tank>
The main polyp area is on a huge rock that supports a lot of the other rock structure, so removal is not possible....well not easy anyway. At first they were quite pretty, now they remind me of dandelions on a manicured yard!
4. Last question and most important....any hints for trapping the sally light foot crab!?!
<Box traps... you can buy as such or just the plastic ones for small rodents (they're the same)...>
Last month I walked by the tank to see the crab eating one of the cleaner shrimp (Arrgh, the horror...I tell myself the crab was merely scavenging, but....).
<Ah, no>
Last week the yellow tang had a tear in the caudal fin. The fin healed, but we are worried the crab is on the prowl. We have tried physically grabbing the crab (yeah, no shock that didn't work) and commercial traps which resulted in one trapped and very stressed clownfish. When we put frozen fish in a jar or on a string to bait the crab, all the other fish grab the treat. We have tried feeding the fish on the other side of the tank at the same time, but they are too clever for that! Assuming we catch the crab, can we just place him in the fuge or would one crab defeat the purpose of the fuge, especially since we rely on the pod production for the mandarin?
<Move, isolate, trade in with the move...>
Thanks for the help as always and sorry for the long e-mail. All of you do a great service to us newbies out here!
Michele
<Congrats on the new, larger system. Bob Fenner>

Re: Random questions/reef tank 9/26/07
Thank you for the reply. Yes, we know the 90 gallon is WAAAY too small for the Naso which is why we are upgrading to the 220. We didn't do our research when we bought her last year, but we are trying to make it right with the new tank.
<Good... I do hope you get on out to the wild... see these active fishes there>
The tank was a custom order this past January right after we got the Naso, but it only finally got here last month!
We had certainly hoped to have her in the larger tank sooner than this.
You have me quite stressed now that the Rabbitfish's coloration is secondary to the small tank....we shall try and get the new tank up and running quickly!
Michele Frazer, DVM
<Do please send along an image or two when it's settled in. Cheers, BobF>

Crab and Candycane comp.  – 08/27/07
Hi Crew,
Yesterday I noticed something on my Candycane. In between the outer brown and the inner green it looked like something got caught on there. So I took a tweezers and it lifted right out but it came out swinging. It is (was) tiny and I doubt if I could have presented a good picture. I usually let things, that I find in the tank, live. But my gut feeling was that this was a bad guy, at least for my Candycane, so my tweezers crunched the perpetrator. It looked like a miniature crab. I do not recall reading about any Candycane pests. I have this candy cane a couple years. But recently I took in a large colony from someone since it was deteriorating in his tank. Maybe it is infected with this pest. I have not found any more yet. Right now the bright green center of the head that had the crab does not look bright and is not very green. The mouth is a large hole and is how many of the heads look in the colony that I took in. Aside for keeping my eyes open for more of these creatures is there anything I should do? Would it be useful to do a freshwater dip to force out any more of these creatures?
<Naw, don't do that. It won't help and would probably just stress out the coral.>
I did not quarantine the sick Candycane because it came from a tank that is much better than mine and my thought was that the other corals were causing it to decline.
<Well, quarantining has nothing to do with how well the tank it came from is/was doing. But anyway… very few crabs reproduce readily in aquariums. So even if this “crab” is a pest, if it’s actually a crab, I wouldn’t worry about it multiplying. Also, you never know if the crab caused the coral’s problems or if it simply took advantage of the coral’s decline. Just keep an eye on the coral. If it doesn’t recover, then you might have to think more about why it’s suffering.>
Thanks
<De nada,
Sara M.>

Added Crabs, Shrimp are Gone; Mithraculus  8/22/07
Hey gang! Boy, if anybody can mess something up it's me.
<I bet I'm worse.>
I had/have an issue with Valonia (sp?) bubbles, it was really severe. I decided against the raccoon butterfly because of issues it might have with my inverts so I bought some small Mithrax crabs..
<Ok>
The Valonia bubbles are receding except for the big ones I can snag with a siphon tube but what disturbs me is the sudden disappearance/deaths of my shrimp.
<Uh oh>
In the past two weeks (since introducing the crabs) I've lost two very large skunk shrimp and one small peppermint shrimp. I took the deceased peppermint out, it seemed to be intact. I only saw the carcass of one of my skunk shrimp briefly this morning but it was gone before I could get it. No sign of the other.
<Dead things disappear very quickly in aquariums.>
Everything else in the tank (2 fire fish, 1 azure damsel, 1 royal Gramma, 1 orchid Dottyback, and assorted corals that have been in the tank since I started over a year ago plus one huge bubble tip anemone and it's large clown) are fine.
Is it safe to assume that the Mithrax have killed the shrimp?
<Definitely a possibility>
I wouldn't have expected it, I figured they'd feast on the bubbles.
<They eat whatever is in front of them.>
Should I trap and remove them?
<Could>
I have a large abalone I'd hate to lose but I am seeing some empty snail shells as well.
<Sounds like the crabs may be your problem but hard to say for sure. If something else is killing the shrimp and snails then the crabs may just be cleaning up the leftovers.>
Thanks for your kind assistance that you generously offer.
Lisa
<If possible separate the crabs into the sump if you have one or another tank and just move live rock in and out as they eat the algae.>
<Chris>

Re: Added crabs, shrimp are gone! 8/23/07
Thanks Chris :) I'll set a trap tonight. I do have a refugium, it's full of Chaetomorpha. I'll add some rock.
<Sounds good.>
I watch the tank at night with a red light, the only thing I notice are the crabs. I'll update when they're out.
<Ok>
Thanks so much for all you do :)
Lisa
<Welcome>
<Chris>

Shrimp vs. Crabs: Overcrowding/mixed species issues - 7/24/07
Hello,
<Howdy>
I have been puzzled over the last few weeks and I am hoping you all can help. <Hope so!> I had a fire shrimp and two cleaner shrimp in my tank and they seemed to be thriving. Very active, the fire shrimp molted several times, and was a brilliant red. <They really are beautiful shrimp> Well, about 2 weeks ago, one of the cleaner shrimp had died, or been killed, and my sally lightfoot crab was eating it. <Sorry to hear that> I figured just bad luck. <More likely a hungry crab> About 1 week later, I added another <!> sally lightfoot <Houston, we have a problem> and within two days the other cleaner shrimp was dead and being eaten by the crab. <Yep, saw that one coming> I started to be concerned, and took some water to the LFS to check it out, and everything thing came back in great range (I'd list it all, but I don't have the exact #'s with me)<Okay>. This morning I awoke to my arrow crab <Yikes! There’s an arrow crab in there too?> and sally lightfoot eating the presumably dead fire shrimp. Now these guys are <aren't(?)> the cheapest things in the world, and I <I'm> wondering if I should buy another one, or not, with the crabs in the tank? <Definitely not!> I have 2 sally Lightfoots, 1 emerald crab, 1 arrow crab, electric blue hermit crab, and a couple Cortez hermit crabs. Is it bad luck <It's more than that> or are they praying <preying> on the shrimp when they molt? <Possibly, but I'm guessing they just like shrimp.> Tank is a 14 gallon bio cube, with a few small corals, 20 lbs of live sand, and 14 pounds live rock. There are some mushroom colonies, a small clown, and purple Pseudochromis.
<I'm sorry for your losses, but unfortunately, the issues here are: too many different/incompatible shrimp/crab species, in too large a quantity, in too small a tank. If you want to keep shrimp, I wouldn’t put more than a single specie in a 14g BioCube, and no crabs. Crabs in general are not a good idea in mixed reef situations, much less in high concentrations. Sally Lightfoots and arrows, in particular, are known to kill small to medium fish and invertebrates – pretty much anything they can get hold of. Emerald/Mithrax crabs can go either way, IME. Sometimes you get lucky, sometimes you don't. While it’s possible that the actual deaths of the various shrimp could have been due to other factors (stress of overcrowding, starvation, etc), it’s most likely the crabs did the killing. I would decide on keeping one or the other, and trap/return the rest. I would also recommend reading the FAQ’s, and info at WWM re: keeping/compatibility issues for these species, and prior to any future additions.
http://www.wetwebmedia.com/marine/inverts/arthropoda/shrimp/cleaner.htm
http://www.wetwebmedia.com/swcrabcomp.htm
http://www.wetwebmedia.com/arrowcrabfaqs.htm
Good luck!-Lynn>

Re: Shrimp vs. Crabs: Overcrowding/mixed species issues - 7/25/07
<Hello!>
Wow, you guys/girls are awesome, thanks for the information and the advice.
<You’re very welcome and thank you for writing in! Although it’s too late to save your little shrimp, your shared experience could save others down the road! – Lynn>

Stone Crabs! - 7/18/07
<Hi Bridget!>
I have pulled 3 of these guys out of my tank in the past 6 months. <Yikes!> Pet store ID'd the last one and advised an elimination program. All research on the web tells how tasty they are. <I’ve never had them, but I’ve heard that as well.> That really is kinda useless. <Well, if you do indeed have the same variety of "stone crab" that they use in the seafood industry, you can try Googling its scientific name: Menippe mercenaria. That's the problem with common names, though. One name can be used for many species.>
My biggest question is, are they really all that bad?
<Well, not if you want a crab tank! If you want a reef tank with snails, etc, in it, then yep, I'm sorry but they’re bad. Crabs in the Menippe genus are xanthid, or mud, crabs and have a bad reputation for being destructive in reef tanks. Also, some Xanthids are toxic, so just in case, don't let anyone eat those crabs!>
If so what's your best advise for removal?
<Please see this link and the post labeled “Trapping in Displays”: http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/swcrabfaqs2.htm >
I do know I no longer have any hermit crabs and my yellow tang has gone missing? <Hmmmm, not good.> Now have 3 fish in the 75, 2 true Percula's and one coral beauty.
Thank you for your time
Bridget
<You're very welcome, and good luck! -Lynn>

Re: Stone Crabs! Follow-up 7/19/07
<Hi again, Bridget! Lynn here.>
Well I found some pictures here http://www.okeefes.org/Crabs/crab%20photos%20and%20scans.htm and this guy <(Pilumnus sayi)> is definitely what I have and not the stone crabs <(Menippe mercenaria)> *Pilumnus sayi*
<Thanks! Pilumnus sayi, sometimes called the hairy mud crab, or spineback hairy crab, has those same robust claws as the yummy stone crabs (Menippe mercenaria) but with lots of bristles! Unfortunately, it’s still a xanthid and potential trouble down the road for a mixed reef tank.>
Hubby is being a grump and not wanting to remove these guys.
<I can understand that. As much trouble as they can cause for the other inhabitants of your tank, they’re still neat little creatures! Why not set up a separate tank for them? It’s a win-win!>
Myself, I'm more than concerned about the quantity and I'm wondering if they might be reproducing or if they just came in with the live rock.
<Almost guaranteed that they came in with the rock. The juvenile stages of crabs have a next to nil chance of surviving in the average tank.>
I don't see these guys. They're professional hiders, <Yes indeed!> I'm only finding dead bodies.
<Of snails, etc, or the crabs themselves? If it’s snails, etc, that’s not too surprising. If it’s crab bodies, they could just be the shed shells from when they molt.>
Which makes me more concerned about anyone else in the tank.
<Understandable either way!>
Tank is a 75 reef established 3 years, new live rock with oysters 6 months ago.
<Sounds like a nice tank to me!>
Thank you for your time.
Bridget
<You’re most welcome, Bridget. I’d try to trap these guys (see previous link on this) and set them up in a tank of their own. Good luck! -Lynn >

 Re: Stone Crabs! Follow-up: Mysterious losses - 7/19/07
<Hi Bridget!>
These are definitely dead crab bodies. I've had several crabs/shrimp that have molted and it's fairly easy to tell the difference.
<Yep, sorry about that. I figured you probably already knew, but wanted to be sure.>
I saw the last one the night before hanging upside down on the rock and he was a pinkish red color which told me he wasn't feeling good. Next morning he was sitting on the bottom of the tank. I had to really fight to get him loose. He'd latched onto some plants, and a rock, and wasn't wanting to let go.
<The loss of these little crabs may be a simple matter of too much competition for food. By the way, if you have any shrimp, have they been shedding normally? If not, you might want to check the iodine level. Insufficiency here could explain some of the other invert deaths as well.>
I still have the whole body sitting here in a jar in front of me so I can reference back as I'm searching. My biggest concern was reproduction.
<No worries there. True crabs, such as yours, hatch into a planktonic zoea/larval stage that, without special food/care, have very little chance of survival in a tank. They drift along in the currents, and become part of the food chain.>
Now I'm going to set up the pickle jar tonight. After doing the reading I started searching the tank for lost residents, 3 queen conch, 12 hermits, and about 20 odd ball snails, missing. Past 6 months or so yellow tang, purple fire fish and blenny have disappeared. Crabs need to go.. huuummmm
<Yep, that’s a lot. If water parameters and chemistry are/have all been fine, and there’s been no apparent disease/injury, and finally, there’s been enough food for all those inverts, then you have to consider predation. I’d definitely put a trap out and see what you get. Just out of curiosity, have you heard any popping or clicking sounds coming from the tank, especially at night?>
Reminds me, walked into the fish store and told them I had crabs. You can imagine those poor young men trying to keep a straight face. LOL
<LOL!! They’re probably still laughing over that one! I know it’ll keep me going for a while!>
Thank you Lynn for all your help
Bridget
<You’re very welcome, Bridget, and thanks for the laugh!>

Re: Stone Crabs! Follow-up 2: Mysterious losses - 7/19/07
<Hi Bridget!>
No strange noises, but we turn off the tank and go to bed. Will let you know. <Sounds good.> You've been great. <Happy to help - I just wish I could have been more so!> Water is good, corals, mushrooms and anemone are growing and healthy happy.
<Terrific!>
Thanks so much
Bridget
<It was my pleasure! Take care –Lynn>

Re: Stone Crabs! Follow-up 3 - 7/20/07
<Hi Bridget!>
Nothing this morning, will change location, feed less at dinnertime and shrink the jar a little and try again. <Yep, trapping can take some time/patience/luck. Using “stinky” bait (shrimp/squid/etc), should help.> Hubby seems to think that we may have lost some of the crew with the spike from the new rock, it's a good
sized rock, 35lbs <Yowza! It’s entirely possible, especially if it wasn’t cured. Even if it was, though, it still would have caused some chemistry changes.> with 7 oysters on it, <Neat> one tunicate that I adore, he's about 3" tall, bright orange. <Pretty!> We got the oysters for added filtration, and they are reproducing rather quickly. <Sounds like they're happy!> It also came with some non photosynthetic stony coral on it, it came with 3 polyps on it and now there's six of them. <Nice!> Also have something that looks like it might be a baby bubble tip. Except it has this long curly tongue kinda thing that hangs out, when hungry. <I've got a dog that does that when he sees ice cream.> Cream and pink colored about 3/4" around and impossible to photograph through that thick glass. <Understandable, that can be a challenge.>
Will update again as soon as I have any news <Please do!>
Take care <You too, and have a great weekend! –Lynn>
Bridget

Please help!!  Clown and Crab Interaction 7/13/07
Good Afternoon guys (and gals),
<Hello>
I have a 10 gallon FOWLR (&LS) set up with a Skilter skimmer, maxi-jet 600, and very stable readings for two weeks straight after cycling for 5 weeks.
<Ok>
Last night I added a false Perc and a sally (she was a throw in from the person I bought my Perc from). After using the drip method for acclimation I have noticed that my false stays on one side of the tank and the sally roams free. <Not unusually for a clown, although you want to watch him closely.> I think I noticed (could be paranoia) the crab stalking my clown. <Possible> I think its nothing more than paranoia but I am really getting worried about the crab trying to attack my Perc. <Crabs eat whatever they can catch, and Sallies have been know to catch small fish.> He is constantly looking for her and it appears to be scaring my clown. I looked on DFWMAS.org and I got differing answers....I am about 99% certain I have nothing to fear but after reading up on my totally unexpected and unprepared for sally it appears he wont be in my tank for long regardless. <Probably the best move.>
I guess my question is whether or not I should be concerned with the sally eating my clown. <Can happen, although not too often.> Other than looking totally freaked out whenever the crab "appears" from the rocks he/she is doing great and eating. I see no markings on (we'll go with her) her and she is very active.. albeit on one side of the tank.
Thank you in advance for you help
Phil Murphy
<Welcome>
<Chris>
 

Re: Red Fromia star has hole in its head! Help!   4/4/07
Mich, Thanks for the reply.
<Welcome!>
The star ended up dying.
<I'm sorry for your loss.>
I believe it to either be an acclimation issue OR the teddy bear crab.
<Either are possibilities.>
I went back to the shop where I had acquired the star and there was a star from the same batch that disintegrated also.
<Unfortunately this is not terribly surprising.>
But, to my horror, I caught the teddy bear crab eating my sand-sifting star the next day! It ate a whole arm before I knew what was happening.
<Yikes!  I would not recommend the sand-sifting star (Astropecten spp.).  These stars decimate your sand bed removing beneficial organisms and typically starve after a few months in captivity.>  
Needless to say I have removed the teddy bear crab from the tank.
<Mmm, hopefully to a suitable home and not an untimely demise.>
I had searched online about the teddy bear and various sites said it was reef safe and a detritus eater so I thought it was safe, thanks for the info that says otherwise....wish I would have known.
<Not every source hold equal value.>
Hopefully the star will live and regenerate a new arm.
<It may.>
Unfortunately, none of my corals are happy since adding the sponges. The tank at the store that one of the sponges was in was being cleaned when I bought it (water was really cloudy). I'm starting to think that I introduced a lot of toxins since I had to introduce that water into my tank.
<Yikes!>
I am going to do a few water changes daily for the next few days to get any toxins out.
<Do watch this carefully.  Dying sponges can really do a lot of damage.>
Green mushroom won't open up, gorgonian won't come out and my torch is losing tentacles!
<Ho buoy!  Not good!>
I'm about to do a water change right now.
<Good!>
I changed it yesterday and the gorgonian came out for a while.
<You may need to do several large changes here!>
Wish me luck!
<Good luck my friend!>
Thanks again for the info,
<You are most welcome!  -Mich>
Luis

Hermit's a tripod now???   3/11/07
I have recently noticed that one of my larger--actually the largest of my red tipped hermits has lost many of his legs.  
<So the Vietnam was is raging in your tank?>
He currently only has his pinchers and one left leg.  He is unable to walk or climb.  The only thing that he can do with seemingly great difficulty is turn in a circle.
<This is to be expected with a Septa-plegic.>   
I have been hand placing food in front of him for the past couple weeks to prevent him from starving.  
<As long as he is eating it, and you can continue this, after a few molts, the crab should start to grow new legs.>
All of the other hermits are fine.  -----Is it normal for this to happen to this degree?  
<It is never normal for inhabitants to start losing limbs.  The Sally Lightfoot that you mention below is a likely culprit.  Actually, if you have a refugium, or another fishless tank to put this one in, I would do that.  Eventually you will be E-mailing us wondering what ate your fish.  The answer will be the Sally Lightfoot.>
My water parameters are and have been in perfect or near perfect range for over a year.  I only have a couple of Damsels, Chromis,  O. Clown, Sally Lightfoot, snails, smaller hermits and corals in my tank. My biggest worry is that I am only prolonging a horrible life of  immobility!  Is it possible that he will regenerate his 3 lost legs?
<Please see above.>
Or have I literally made him a "sitting duck"?  Any thoughts would be greatly appreciated!!
<I hope this helps, Brandon.>

Problem with <true? or hermit, really> Crabs and Overstocking – 2/20/07
Help!
<Hi Janet, Brenda here tonight>
I have been reading through your FAQ’s and reading elsewhere and I am not finding the answers to my question.  Since November 2006 I have had a 24 gallon Aqua Pod.  All my parameters are within the required limits. I do a weekly 4 gallon water change to keep my nitrates down.
I have 4 fish (yellow-tail damsel, 1 clarkii clownfish, and 2 percula clownfish), there are snails and crabs, mushrooms, an anemone (the clarkii loves it there), a sea urchin, a blue star fish, frogspawn coral, feather duster, star polyp, Caulastrea, Galaxea coral, yellow pagoda, Zoanthid, and 2 cleaner shrimps.
<Oh my!  You're way over stocked.  You will also see aggression between the percula and clarkii clownfish as they mature.  You shouldn’t mix corals and anemones, especially a nano tank.  The Galaxea has sweeper tentacles that can reach up to 12 inches, the frogspawn also has long tentacles and the Caulastrea up to 2 inch tentacles.  These tentacles will sting all your corals and your invertebrates.>
I had (and these have not survived) a electric flame scallop, black sun coral, pearl bubble coral, brain coral, and Fungia.
<I’m not surprised.>
I feed them 1X a day ~ I alternate every other day with the following Mysis shrimp, Cyclops eeze (originally for the black sun coral), and prime reef flake food.  
About a month ago, I took out 10 crabs (I had 20) because they seem to be eating other things in the tank besides the garbage.
<It is recommended to have 1 crab or less for every 10 gallons.  I don’t recommend crabs with anemones.>
Now they seem to be eating snails
<This is common they can also eat small fish, corals, and nip at anemones.>
and they look they are eating each other, too.  
<Have not heard of this, could be the sweeper tentacles.>
It, also, looks they have multiplied.  What do I do?
<Decide what sort of tank you want to keep, anemone or coral.  If you choose coral, select those that are not as aggressive.  Please research compatibility and care before your purchase.>
Janet
<Brenda>

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>

Emerald crab and cleaner shrimp  - 09/01/06
Hello! <Hi Christy, MacL here today.>  Thank you for all of your help from the past, present and future! <You are so kind and we all appreciate it.>
Three days ago I added an Emerald Crab to my 25 Gallon saltwater tank, 1.022 spg, ammonia 0, nitrite 0. I bought him to control my Bubble Algae. My current residents are a Scarlett Cleaner Shrimp, 2 Blue-Green Chromis, 9 Purple Mushrooms, 2 Red Leg Hermit Crabs, 8 Turbo Snails. Before I purchased the Emerald Crab, I researched and came to the conclusion that large Emerald Crabs could possibly pose a threat to small fish or crustaceans if it was hungry, but most likely a small Emerald Crab would do no damage to the other residents of my tank. <Unfortunately Christy, small ones grow to large ones and to be honest I have seen them cause problems at all sizes.>  I haven't seen any sign of aggression between the shrimp and crab. My shrimp molted last night, and I didn't notice his antennas being any different earlier today, I'm not sure if I just hadn't noticed or not, but now tonight.. I've noticed that all of his antennas are considerably shorter than before, except for one which is the same length. <It is definitely possible for something to have occurred during the molt which caused the antenna length to change.>
I'm having a difficult time believing that my less than one inch Emerald Crab could have done that. I also can't find one of my Chromis anywhere! I'm now worried that I've got a little green goblin in my tank! My question is could anything have happened to my Shrimp's antennas other than the crab getting hold of him? While molting, could he have lost his antenna length?  <My philosophy on this is pretty simple, if things were good before I add some creature then I start having problems after I add them, then I usually take the new creature out.>
On a different note.. I have a question about my shrimp's molting
regularity. He molts almost every week the morning after a water change. Is it bad to molt so regularly?  <In my experience he's molting way too frequently. Are you adding supplements to the water like iodine?  That can cause them to molt more frequently.  There is a great section on molting in general in shrimp on site, I'd encourage you to take a look at it.  MacL>

Crabs in my house   6/27/06
I live in Hampton, VA near a marsh, and we have been having a lot of rain lately.  Last week and today there were a lot of crabs in my garage.  Is there any way to keep them out of the house?
Judy
<A row of small melted butter dishes? Actually, installing a flexible guard under the garage doors setting edge is what I would do. See Lowe's, Home Depot... re. Bob Fenner>

Re: Crabs in my house  6/27/06
Thanks for the tip.  Actually, I had thought of putting down some Old Bay and hot sauce!
<Heeeee! Tasty! BobF, with a bib on>

The tiniest crab?? ever inside a candy cane coral   4/6/06
I just bought a white/extra gum green candy cane coral and just noticed a small hole in the tissue and what appears to be a very tiny crab in it (approx. 3mm) is this uncommon and a reason for concern?  I am a wee bit worried- how will i remove the crab if needed?
thank you,
Russell Thomas
<Common (though not often observed) and not a problem... though semi-parasitic in nature, these two organisms live together in the wild. Bob Fenner>

White spotted crabs in trouble... just natural predatory beh.   - 03/26/2006
Hello and thank you so much for what you are doing! the life of my crab is in your hands.
<Actually yours... my keyboard is all I can touch here>
I have a 55 sw tank that is only 2 weeks old. We got our 2 big , white spotted crabs along with 5 hardy fish(1 of them is in quarantine now) <This tank is too new...>
They have been very happy at fist, crawling and exploring our tank happily, but not spending any time together. With time though, Hulk (the bigger sized crab) started to attack Harold (a bit smaller guy) periodically. If we didn't feed him as often as he wanted he would attack him as if to say: if you guys don't feed me now I am going to eat Harold.
<Will... not William, just will>
I interfere when he attacks, pulling him off the poor guy. Now, even after we added shells, Hulk was
still a bully, and Harold is now a recluse, refusing to eat, and spending his time motionlessly perched on the very top of our LR mountain.
<Some symbology now!>
And he used to climb the funniest places, like our filter tube, and be very active.
<And trying to escape...>
Now I checked our water and it is ammonia and nitrite wise safe. However, our heater seems to be broken and the temperature has soared to 81. Could this be the problem?
<Not likely>
I am replacing the heater today and have it disconnected for now. Unfortunately, Hulk has also attacked our only snail and she is motionless, too... But it's breaking my heart that Harold is not even eating and probably not going to molt, since he is nowhere near the sand but instead, climbed the highest point in our tank as if to beg: get me outta here! Please, any advice, tip, suggestion, anything at all to save the poor guy?
Angel.
<... another tank, or trade in the aggressor. Bob Fenner>

Re: White spotted crabs in trouble -- MURDER IN THE TANK!!!    4/6/06
As an update...the smaller guy has almost killed the bigger guy today. Ripped him in half, his guts are outside,
<Ah... a goner>
chopped off his 3 legs, 4th fell off. We put him in separately, we don't know if the injured crab will survive.
<Not likely>
I don't have the heart to just pull him out so he is on his own, with his favorite shell, slowly dying... Is there anything I can do, any medicine to speed up healing, what do you recommend to do at this point???
We are so sad.
<Mmm, not to be... inevitable... I'd monitor ammonia, nitrite... likely will be "totally" consumed... and soon... if not already. Bob Fenner>