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FAQs about Sea Urchins, Sand Dollar Systems

Related Articles: Sea Urchins

Related FAQs: Urchins 1Urchins 2Urchins 3, Urchin Identification, Urchin Behavior, Urchin Compatibility, Urchin Selection, Urchin Feeding, Urchin Disease, Urchin Reproduction

Tuxedo urchin; BGA hang ons issue      11/13/15
Hi, I hope you can help (or confirm) this little oddity about Tuxedo urchins.
I've had mine for almost a year now, and in the last six months everything he picks up becomes covered in red Cyano?
<Opportunist... conditions in the system are allowing the BGA to establish itself after a "grinding" from the Urchin. Increased RedOx especially (and what it takes to get there really) is the measure to use to guide the success of efforts in improving water quality (more circulation, less dissolved organics); possibly the incorporation of a live sump/refugium, RDP lighting there, macro algal culture.... Spiffed up, improved skimming, use of chemical filtrants like GAC, PolyFilter, adding a bit more live rock, fine substrate to enhance the DSB...>
I have absolutely no other cyanobacteria in my system. I make sure I relieve him of his infested trinkets, only for him to pick up a few more which become covered in a matter of days??
<Again; environmental improvement>
Are they known to do this?
<Mmm; yes; as are all Urchins really... they have "pincers" that penetrate the test for keeping such off their exteriors, but not the spines themselves>
Thanks for any insight,
<Welcome. Bob Fenner>

Sand dollars in reef tank? Hi y'all <Mikkel> Just a quick question: My LFS has started selling sand dollars (Clypeaster) but the staff doesn't know the first thing about them (kinda scary!). I've done some research myself and it does look like it could be a fun and beneficial addition to my 180g reef - http://animaldiversity.ummz.umich.edu/site/accounts/information/Clypeaster_subdepressus.html <http://animaldiversity.ummz.umich.edu/site/accounts/information/Clypeaster_subdepressus.html> . ....but is it really? I've Googled the stuff out of it, but can't seem to find any references to keeping it in aquariums. TIA Mikkel Boisen     <These echinoids are kept (used to collect them myself as a job in college) for science and demonstration purposes... and have seen various species displayed in public aquariums... Would likely live in a well-established reef with deep, fine substrate, good circulation, a vigorous, large refugium. Bob Fenner>

Salt Mixed in Tank <Hello, Ryan with you> Hi, I just bought a black spined urchin yesterday, (diadema setosum) it was ok when we put it in the tank, it was walking around. My husband needed to add some salt to the tank and when pouring it in some fell on him. <OH MY! You need to read the directions on your salt mix. They clearly state that you must mix the salt in a separate container.> Now he is not moving and some of his spines had fallen down. <He is in shock, in more ways than one. You have put him in a new environment, and then changed it.> Please tell me if he is dying (I hope not). <I think so, but give him time> I don't know what to do. Please A.S.A.P. <Please start reading about this hobby. You're here, so that's good. Start here: http://www.wetwebmedia.com/marine/maintenance/marineMaint.htm . You need to take a look at what a saltwater aquarium requires, and decide if it's for you. Good luck, Ryan> Thank you, Kris 

Urchin question, stocking too.... Hello! <hi> Once again I've come for advice on my tank....the first question is about a tuxedo urchin. I have a 55g tank that has been running for 3 years. Coralline algae covers the back glass, both ends, powerheads, intake tubes and about 75% of the LR (there is maybe 50 to 60 lbs of rock in the tank). Do you think that one tuxedo urchin will deplete the coralline? < no one will do fine you can place Nori in and they will feed on that > I would really like to have an urchin, but at the same time, I like the looks of the coralline algae too....will they also eat other algae? I also have on several of the rocks, an encrusting algae that looks like crushed velvet, a deep magenta color, that I would hate to lose too....(BTW, this is not slime algae, I have never been able to ID what exactly it is, but it is extremely slow growing and does not require much light, very low flow too Next is a stocking question. Same 55g tank, 50 to 60 lbs of rock, DSB....in this tank is a yellow tang (she is about 5 1/2 long, I've had her for almost 3 years and I don't think she will get any bigger), a ocellaris clown, a black Dartfish and an orange tailed damsel. There is also a pair of skunk cleaners, several large Featherdusters, numerous small ones, some mushroom corals and two colonies of Porites. Is there any fish at all that I could possibly add that would be able to stand up to the damsel (my biggest worry) and would not eat any of the inverts? Bannerfish, another damsel, anything? Or am I (as I suspect) unable to add anything at this point??? <you could try a Genicanthus angel there are about a dozen kinds they are totally under rated you will love these fish make sure they are healthy and eating before purchase. Thanks Mike H> Thanks for your help!! Best regards, Sam

Urchins chewing through power heads - 1/28/03 I have a sea urchin emergency and hope that you might be able to offer advice... <I will do my best. Sorry for the delay>   I bought a new, large protein skimmer for my tank.  <Always a good thing>  Today, I looked in the tank and the urchins were motionless and the skimmer was off.<Uh oh>  It turns out that they have chewed through the electrical wire. <Does happen> It seems obvious now, but it never occurred to me that they might do this! <Easy thing to forget. No worries, does happen sometimes>   The urchins have obviously been traumatized but are alive.  <OK. Here is what I suggest: Pull the powerhead (probably already did and be sure to unplug it before putting hands in the tank) remove the urchins (if you can to a rock or more observable area of the tank), do a water change of about 30% would be fine. (there will not be enough copper released from the wire, in my experience, to warrant a full 100% water change. As soon as you see the spines sort of droop (the stage right before falling off) then remove the animal as there is no coming back at that point. Once you see the spines begin to "lay down" for lack of a better word, there is rarely recovery. This is very different from the occasional drop or break of a spine. This will be all or most of the spines doing this all at one time.> Is it more urgent to: 1) leave them in peace to see whether they can make it; <More or less> or 2) change all of the water immediately in case they were exposed to copper from the wires? <about 30% would suffice, in my opinion>  I immediately changed all of the filter media, then it occurred to me that the copper might actually be more of a problem than the initial shock (since everything automatically turned off right away). <Likely, with the exception the copper is not as soluble as one might think. In liquid form it is deadly, but there is very little residual coming off a solid wire with exposure if only for a day or two.> Do you have any suggestions to help save my urchins? <Hopefully those above will help> I accept that I am an idiot and perhaps should be banned from purchasing salt water inverts ever again...<No way. Never talk like that. It happens and some things cannot always be foreseen. Don't be so hard on yourself. Many more mistakes to come your way. That is why this hobby (heck, most hobbies) have such a science to them. More I learn, the less I seem to know for sure. Good luck. ~Paul>

Shocking urchin emergency I just sent an e-mail about my urchin emergency (they tried to eat through the electrical cord on the protein skimmer).  May I humbly suggest that you might want to list this potential hazard in the next edition of Reef Invertebrates?  Yes, it should be obvious - but perhaps someone else might be spared the same accident. Thanks for any suggestions you may have - I understand if you have none. <Yeeikes! And they (Urchins) have the ability to chew through most anything... I would either lift the chewed part of the wiring entirely out of the water, inspect it and seal it (see an electrical shop re) AND arrange the wiring such that the urchin/s can't get to it, either out of the water with the heads up near the surface or protected by solid rock work. Bob Fenner>

Sand dollars... not for aquariums... at all Hey Bob. This is my first time writing to you. <cheers, Travis> I have 2 tanks currently. First is a 55 gallon tank. 85 lbs. live rock, 60 lbs. live sand, two emperor 400 and a Bak Pak 2 skimmer. I had a dragonet but I don't think he is with me anymore. <indeed... very difficult to keep long term (especially in a smaller tank) without fishless refugiums producing plankton. Most starve to death in a year or so... a few hang on longer> I had a fish that would pick on anything he could. I have since removed him, do you think it would be good or bad to try again? <not at all> My other tank I have set up for sea horses but no horses. 10 gallon, Sea grass and dead hardened sponges for there tails. Well, My little girl thought it would be a good idea to keep three small sand dollars south Florida) they are currently in the small tank pretty much alone. <oh, no :( > Are they safe? Can I put one or more in the big tank? <sand dollars should be left in the ocean, my friend. They are extremely difficult deposit feeders to keep alive in captivity requiring staggering amounts of aged live sand to even have a chance to survive. Some of the most common figures bandied about include sand beds that are 6" minimum and 6 ft square! per single sand dollar. Such sand needs to be aged more than a year too. Truly an animal for XL aquaria and experts. Yours will starve to death slowly (6-12 months usually) without a change of residency> The big tank has three sand stars. Do they have poison which could be dangerous? <not likely... but do ID by species to be sure. Also, know that some brittle or serpent starfish will attack and kill/eat seahorses like the Green brittle starfish (incrassata)> What about when I put the horses in there? and anything else you can think of. Thanks so much Travis Morris <your seahorses will benefit tremendously from a refugium... do research the aspect mate. Kind regards, Anthony>

Sand bed Hi, Bob and good evening. I'm still confused about this sand bed and live sand. Somebody on the net tells me now that the live sand my dealer sells has only bacteria in it, but none of the important "critters" that I need to get the sand sifted. <This is possible. There are such products.> They suggest that I put 3" of sand collected on our beach on the bottom. Then 2 bags of the live sand from the store and on top of it 1" real live sand from our beach collected in 3' of water. That would give me all the critters. <A dangerous proposition... pests, parasites, pollution too likely present. I would just use some live rock with whatever source of substrate... the LR will inoculate it fine> Can any phosphate in the sand be filtered out later? <Mmm, yes... or bio-accumulated.> I might find a stretch of more or less clean beach not too far away, but we still have rivers and the city polluting the ocean. I find a lot of 'sand dollars' close to the beach in the ocean. Is that a sign of good water? <Not necessarily> Can those animals live in a tank. <Yes. There are public displays of these echinoderms about. And many labs utilize Sand Dollars for research...> I never read anything about them. They bury in the sand. Why the big difference in the depth of a sand bed. Will a 1.5" bed not work biologically? <Depending on depth, chemical make-up, angularity, s/b fine. Please start reading here: http://wetwebmedia.com/marsubstr.htm and here: http://wetwebmedia.com/livesand.htm> Now that I have solved my problem with the temperature, I have another one. I had 2x20 W and 1x15W bulbs on my tank, but now I can fit only 2 x 20 W light fixtures on the remaining glass covers. The rest is open for ventilation. Will 2 x 10 000 K bulbs be enough for the FO tank? <Yes. Bob Fenner> Thanks, Bernd
Re: Sand bed
Hi, Bob. Thanks again for Your well appreciated help. I now have enough new stuff to read. Good night. Bernd <Chat with you soon my friend. Bob Fenner>

Sea Urchins Bob, I have a relatively new 180 acrylic reef tank. It was upsized from a 150. I have some green hair algae, more than I would like. My three tangs won't touch it. I am thinking about buying a couple urchins for control. Will urchins scratch acrylic? <They can, but not usually... but there are other avenues of algae control I would engage... please read: http://www.wetwebmedia.com/algaeconMar.htm and the links beyond> If not which ones would be the least damaging bulldozers? <Please read the pertinent sections of WWM re. Bob Fenner> Thanks, Jim

Sea urchins I tracked down your website after reading over the reviews of your book on Amazon.com. I've ordered the book, but, according to the index, it looks like there are only a few pages specifically dedicated to sea urchins. <Yes> I've been reading the site as well, but thought maybe I'd try asking directly. I'll summarize the background below, but basically my questions are: 1. Are there any changes in conditions that can be used to help coax urchins back to health? For example, do slightly warmer temperatures help? <Depending on species, yes... or lowering... often troubles with a lack of alkaline reserve, biomineral concentration... but the vast majority of "reasons" for mortality are cumulative insults from collection, handling...> 2. Is it possible to keep an urchin-only tank, or do I have to create a full-scale marine aquarium? <Very possible to have a "species" or "concept" tank... often done in the sciences for demonstrations (embryology principally)> 3. If urchins become ill by developing spots and losing spines, is there any way to successfully treat them? <At this point, usually lost... but there is always hope... environmental modification, soaking in antimicrobial compounds...> 4. What is the recommended long-term diet for sea urchins? I've used a combination of algae and "urchin cookie" (containing carrots, egg, egg shell, gelatin) and invert food - but I'm not convinced this is the best. <Mmm, once again... species dependent. A good idea to encourage you to do a bit of look/seeing of the scientific literature. Please read here: http://www.wetwebmedia.com/litsrchart.htm> Basically, my problem is that I need to coax some urchins back to health and my situation may be a little different from normal invert acquisition and setup. I've talked with urchin researchers and with people at the Chicago Aquarium, but seem to find that there is very little information available. <Not much in the hobby literature, the Net, no> Unfortunately, I teach an embryology class and sea urchin embryology sets seem to be designed to be completely disposable (I have complained to the suppliers, but it doesn't seem to get me anywhere). <Ahh, you don't have to toss the animals after extracting gametes... can be rinsed, coaxed back to health> I'm trying to keep all of the urchins, but obviously they get off to a bad start by being shipped cross-country and then injected with KCl (I'd planned to use electrical stimulation, which is less harmful, but received a species that can only be stimulated to release gametes using KCl). <This is S.O.P.> Anyway, I used minimal KCl and the six urchins are currently recuperating in a 20 gallon tank with a canister filter, protein skimmer, and 1.020 salinity. <Mmm, I would keep them in nearer to 1.025 spg> I also use water that has been filtered through a Tap Water purifier, then reconstituted - plus I added Dechlor treatment to the water about a week before the urchins were placed in it. The last time I tried to do this, the urchins did well for about 7 months, then developed some type of infection, lost spines, and died despite treatment with Chloramphenicol (recommended by some urchin researchers) <Yes... but/and do to aplastic anemia concerns, not available directly to the public... Posted for browsers> and isolation of sick urchins. I'd like to avoid repeating that experience if possible. If necessary, I'll set up a proper marine setup - but what do I need to have in order to allow the urchins to survive? By the way, the urchins are L. variegatus. <The genus and site of collection please. Bob Fenner> Do you have any suggestions? Thanks very much. -Ann
Re: sea urchins
Thanks very much for your prompt response. I appreciate the input (I'm a herpetologist; I know little about aquaculture). <Yikes... and have spent many happy and zany moments with herp types... our grad school had the typical arrangement of reptiles, amphibians and fish collections in one building... many non-denatured alcohol and OJ drinks instead of holo- and paratype specimens solutions... Oh, and of course the ASIH...> By the way, can I request that you delete my signature line if you post my message?  <Yes, certainly. Will make sure is done> I wasn't thinking about my message being posted and didn't mean to include my signature line, since I don't want to represent my institution as a whole when asking for urchin info on the web... Thanks. <I understand> > By the way, the urchins are L. variegatus. > <The genus and site of collection please. Bob Fenner> Unfortunately I can't tell you - I didn't collect them myself (Note: I hope to keep a healthy population myself in preference to future collecting anyway, if I can get the husbandry down). <But at least the genus, "L."... is this Lytechinus? Bob Fenner> Thanks again. -Ann
Re: sea urchins
> instead of holo- and paratype specimens solutions... Oh, and of course the > ASIH...> Oops - I just realized that I said that "Indianapolis was fun," when that was HL/SSAR... ASIH was at Penn State! There were too many meetings last year... but all were good. <Ah, academia! Bob F> -Ann
Re: sea urchins
> <Yikes... and have spent many happy and zany moments with herp types... our > grad school had the typical arrangement of reptiles, amphibians and fish > collections in one building... many non-denatured alcohol and OJ drinks > instead of holo- and paratype specimens solutions... Oh, and of course the > ASIH...> Yes, I'm regularly at ASIH... Indianapolis last year was fun! We had one fish person at grad school - but hearing about the otoliths of introduced cichlids didn't give me much information about aquaculture. We were a herp-intensive group. I have a large assortment of herps that I've kept for many years, but urchins are my first venture into real aquaculture. I wasn't willing to throw out the urchins after embryology lab, so I've had to learn a few things since then... I'd never heard of a protein skimmer before. <Yowzah, talk about jumping en media res!> > <But at least the genus, "L."... is this Lytechinus? Bob Fenner> Yes, it is. I believe that they were collected somewhere near the Florida Keys, but I really don't know. I think that Lytechinus variegatus is found around the Keys, these urchins are supposed to be L. variegatus, and these urchins were shipped from Florida. Thanks again. -Ann

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