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FAQs about Sea Urchins, Sand Dollars 3

Related Articles: Sea Urchins An Introduction to the Echinoderms:  The Sea Stars, Sea Urchins, Sea Cucumbers and More... By James W. Fatherree, M.Sc.

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

Black Long Spine Urchin Questions       9/17/19
Hi Bob -
I have two questions for you. I've searched the wet web media knowledge base but haven't found the answers. FYI, I've been working on eradicating cyanobacteria from a 265 gallon and 150 gallon (both FOWLR) with the methods you've outlined. Progress is occurring.
<Sure and steady is the way here. Fast approaches are dangerous; too often lead to anomalous losses to wipe outs>
Questions: Would a black long spine urchin eat cyanobacteria?
<Some, yes... do look (Google?) the genus Diadema re>
I suspect not, but not 100% sure. Lastly, would a green bird wrasse bother a long spine urchin?
<Doubtful; no>
I know they like snails, but thought maybe the long spine urchin would be OK with its venomous spines.
<This genus of urchins, not very venomous... mild; not harmful to humans.>
Thank you, John
<Welcome. Bob Fenner>
Re: Black Long Spine Urchin Questions      9/18/19

Perfect! Thank you Bob!
<Ah, welcome John. BobF>

SEA URCHINS – 3/7/12
Good Morning, I' am Freshmen student from the Philippines taking up Bachelor of Science in Biology. My group and I are studying about the population of sea urchins located in Samal area. We would like to ask for your assistance for the research, to gather some information's and data about our study.
Questions are as follows:
We were using transect line and quadrants to determine the population of the sea urchin our starting point was 82 steps from the coastal area. The transect line(horizontally) were divided into 3 stations. In each station there is a corresponding vertical line for the quadrants to be placed alternately there are 10 quadrants for each station.(see attached file for illustration) When doing the research in the first two stations(station 1 and 2) our results show that there are no sea urchin present but in Station 3 there were few sea urchins present. We would like to ask:
1. What are the factors that might affect the lack of population of sea urchin in our study?

<Sea Urchin distribution will be affected by [1] period of time exposed to the air and degree of dehydration (so direct sunlight and wind may be factors) and [2] the abundance of predators (typically starfish). Other factors to consider would be the presence of humans that collect them or otherwise disturb them, movement of sediment or rocks that prevents them holding onto the rocks, competition for space from other organisms, and availability of food when the are is under water.>
Hoping for your answer! thank you!
<Much written on this topic; see especially scholarly articles on Strongylocentrotus purpuratus distribution in the east Pacific. Studies involving removal of starfish, extermination of sea otters, etc. of relevance. Cheers, Neale.>
thank you very much for the informative answer!:)
<Most welcome. Neale.>
Re: SEA URCHINS    3/12/12

I would like to ask, more likely where do Black long spined sea urchin live? Specifically the Diadema setosum? What might be the factors of their presence in the sea grass area and dead corals or big rocks? -
<This will be in the scientific literature. Do use Google Scholar, then follow the links through to abstracts and papers. There are many factors that will affect distribution, some biotic, others abiotic. Hmm… what else, if you need specifics, you'll need to pay my consultancy rates! As Bob would ask, "What is WWM for…?" Cheers, Neale.>

Urchin: Pedicellariae and Tube Feet -- 3/8/11
<Hello Lisa, Lynn here today.>
I am a research teacher in a high school.
One of my students received sea urchins for her embryology project and many of them are producing these white balls along their spines. What's happening
<What you're seeing is a normal part of urchin anatomy and behavior. In addition to the obvious spines, urchins/echinoids have two other groups of body appendages referred to as tube feet/'podia' and 'pedicellariae'. These are used for a host of functions including locomotion, defense, respiration, feeding, and adhesion. This last function enables the urchin to camouflage, clean, or shade itself by way of grasping and manipulating bits of shell, rock, plant/algal matter, and/or other debris onto, around, or off of the body.
Tube feet/podia present as extendable, flexible stalks that are most frequently tipped with flattened, suction cup-like structures. Pedicellariae, on the other hand, have extendable stalks that are more rigid, with a flexible section at the end that's tipped with a more complex jaw-like apparatus. These 'jaws' vary in form and function, but can be very effective in driving away predators, either by nipping at them, or in some cases (e.g., genus Toxopneustes), through envenomation. For more information, please see the following links: http://www.sci.sdsu.edu/classes/biology/bio515/hentschel/PDFs/Baldonado(2001).pdf
Here's a neat video showing both tube feet (long, translucent appendages) and pedicellariae (shorter, thinner stalks with large white tips): http://wn.com/pedicellaria >
..and is there anything we can do?
<No need, other than to ensure that the urchins are housed/cared for appropriately.>
Please help asap.
<I hope this has helped. If not, or you need any additional information, please let me/us know.>
Thanks Lisa Benincasa East Hampton High School
<You're very welcome, Lisa. Take care, Lynn Zurik>
Re: Urchin: Pedicellariae and Tube Feet -- 3/9/11

<Hello, Lisa>
Thanks so much. You are very helpful.
<You're very welcome; it was a pleasure. Take care, Lynn Z>

Sea urchins Book    6/18/08 Hello Bob, My name is Henk van Noordenburg and live in the Netherlands. Since 1989 I am studying and collecting recent echinoids. The Philippine sea urchins are my speciality. Together with Simon Coppard of the British National History Museum of London, I described a new species from the Philippine region last year . Some weeks ago a new species from Palawan Island was described and named after me. I am the author of the book: "Sea Urchins of the Philippines, Part I, the Irregulars". It is the first part in a series of three. In this book 69 species of irregular recent species that occur in the Philippine waters are described and photographed in detail. The book is recommended by scientists like Dr. Christian Neumann Museum fuer Naturkunde Humboldt-Universitaet in Berlin and Dr. Andreas KrohNatural History Museum ViennaThe book is published by "Artificial Harmonics" in the Netherlands and costs 49,95 Euro ( VAT included). More information can be found on www.artificialharmonics.nl If, for some reason, you cannot open the link, or you have not received a reaction after ordering within two days, just let me know and I will send you the necessary information. Echinologically yours, Henk van Noordenburg <Will post/share Henk. Bob Fenner>

Urchin Hitchhiker: Pencil Urchin - 1/31/08 Hello Crew! <Hi Andy!> About 4 weeks ago, I purchased a large piece of cured Fiji rock to round out my LR aquascape. It is a neat piece, with a big, winding hole running the length of the piece. Even though my LFS claims that the water in the LR tanks are not mixed with other water, I have seen fish in the tanks from time to time, so I placed the LR in my 30 gallon QT for 2 weeks just to be on the safe side. During QT, I can't say that I stared at the LR much other than when checking water parameters, etc. After the QT period, I placed the LR in my tank. About 2 days later, I was shining a flashlight into my tank to check out the nighttime goings on. When I shined the light in the hole of the new piece of LR, I noticed an urchin that is about 2" in diameter (body) (thankfully, the lack of acclimation--twice--didn't kill it!). From browsing WWM, I can confidently tell you that it's some type of pencil urchin, either a Eucidaris tribuloides or a Heterocentrotus mamillatus (my guess, since the LR is pacific, but it has characteristics of the former). <Okay> It is very elusive, so I haven't been able to get a picture of it (or even a good look at it). In fact, for about a week (and apparently, the entire time it was in QT) it didn't move from the cave. Since then, it has made an appearance outside the cave, but only briefly and then on the underside of this same piece of LR. It has now moved back into the cave (who knows where it goes at night). <It goes out to eat! These urchins are nocturnal foragers that, once they've found a nice little protected spot, tend to use it as their "home base". They wedge themselves into place during the day with the help of their thick spines.> My research leads me to believe that it likely poses little risk to its other tank mates--a Sailfin tang, a Gold Stripe Maroon Clown, a Brown Combtooth Blenny, a Royal Gramma, a Copperband Butterfly, 2 cleaner shrimps, 15 or so mushrooms, some type of tree coral (I keep meaning to send in a pic for an ID), a Lemnalia tree coral, two small colonies of pulsing Xenia, and a Trachyphyllia geoffroyi. My tank is 110 gallons, with about 90 lbs of LR, under-the-cabinet trickle filter (in which I run activated carbon that I change out every 2 weeks), a 30 gallon fuge (LR, a huge tuft of Chaeto, and 5" DSB (with about 1 billion bristle/fire worms) on a reverse daylight cycle), and a Coral Life Super Skimmer. My water parameters are: ammonia, nitrite, nitrate and phosphate all 0, temp 80*F, Alk is 3.5 meq/L, pH is 8.3, calcium is 400, and spg is 1.026 (I have a Salifert I2 test kit and a SeaChem iodine test kit, both of which show no appreciable levels, even after dosing with Kent Iodine over a period of days--I've since stopped adding Iodine until I can figure this out). <Good thinking. Please read over the FAQ's here at WWM, starting here: http://www.wetwebmedia.com/iodfaqs.htm > I use RO/DI water (mixed/circulated days in advance of water changes). <Excellent> I dose, as needed, with ESV B-Ionic 2-part buffer. Probably more than you need to know, but . . . <Hey, it's better to have too much information in these queries than too little!> So, to my questions . . . I'm a little worried about this guy starving, because he doesn't seem to move around much and there's not much on the new piece of LR to feast on. <Hmmmm, well he's undoubtedly moving about at night to feed. That's typical for these urchins. What we don't know is which species it is. Some are mostly herbivorous, while others dine on corals, sponges, tunicates, bryozoans, snails, etc. Some even employ those spines to trap/kill fish, shrimp, and other organisms.> I have tons of coralline algae (too much), but the urchin doesn't seem interested in finding it. An attempt to plant Nori would meet with immediate failure, as the Sailfin Tang and Blenny would make quick work of it. <Well, the good news is that these fish aren't nocturnal. I'd rubberband some Nori, or a seaweed sheet, to a rock and place it near the cave after the lights go out.> I have shrimp pellets that I use to feed my fuge--should I try dropping some of those in the display at night? <You could certainly give this, or a bit of clam/squid/etc a try. It's going to be tough though, to keep the shrimp and/or any other nighttime critters from running off with it. To get around this, try to put the food as close to the urchin as you can, and give the shrimp their own little bits to distract them. Is it normal for these urchins to remain fairly stationary? <During the day, yes, very normal.> I would think not. Also, am I correct that the urchin poses little risk to my sessile inverts? <Again, depends on the species/individual. These urchins are generally not considered reef safe. Not only because they can be predatory, but because they tend to bump into things with resulting damage to corals and sometimes your carefully arranged aquascape! For more information/photos on this family of urchins, please see these WWM links: http://www.wetwebmedia.com/urchinsii.htm http://www.wetwebmedia.com/urchinfdgfaqs.htm > Thanks for the help/info. Andy <You're very welcome, Andy. Take care. -Lynn

Passengers on our sea urchin  1/8/06 My classroom saltwater tank has, among other things, a purple (short spined) Atlantic urchin.  It already has a few calciferous tube worms on it.   Recently, it developed what appear to be fuzzy colonies of something on several of its spines.  On one, the "fuzz" is pink and sponge like(?). <Mmm, hydrozoans likely> On two others, the fuzz is lavender and seems to have clear, 1-2 mm tunicates on it.  Do they grow is colonies like that?   <Can, yes> And will it hurt our urchin?   <Very doubtful. Perhaps more of this grows on captive specimens exoskeletons than the wild... but not harmful> The kids have taken to calling it the "walking apartment building"...  It's still eating normally, and cruising around the tank at good speed. -Laura <I wish you had a few more specimens... to grow under different conditions... Bob Fenner>

Looking To Help The Urchin Guy - 12/25/05 Hey guys, <<William>> I came across this post and wondered if there was any way to contact this fellow as I am interested in taking ALL of these Urchins if he is still wanting to rid them.  I am willing to pay any and all freight cost to get them to me.  If you could pass my e-mail to him it would be greatly appreciated. Thanks William Holland <<Hmm...I don't have the email address for the individual in question.  Perhaps Ken will see this post and respond re.  EricR>>
Re: Looking To Help The Urchin Guy - 12/26/05
O.K., I'll hope for the best. <<Me too>> If he does come across this post please pass my e-mail to him or even feel free to add it to the post. Thanks again, William <<I Shall do so William, I kept your email address just in case.  Thank you for your interest, EricR>>

Exotic urchins 6/31/05 I am in need of large amounts of information on these species: Mespilia globulus Echinothrix calamaris Asthenosoma varium Asthenosoma ijimai Astropyga radiata Diadema savignyi Diadema setosum could you help me? <The following URLs contain search results for the urchins listed: Mespilia globulus: http://www.google.com/custom?hl=en&lr=&ie=ISO-8859-1&cof=BGC%3A%23FFFFFF%3BT%3A%23000000%3BLC%3A%230000CC%3BVLC%3A%230000CC%3BALC%3A%230000CC%3BGALT%3A%23008000%3BGFNT%3A%23000000%3BGIMP%3A%23000000%3BDIV%3A%230000CC%3BLBGC%3A%23FFFFFF%3B&sitesearch=wetwebmedia.com&biw=944&q=mespilia+globulus&btnG=Search Echinothrix calamaris: http://www.google.com/custom?hl=en&lr=&ie=ISO-8859-1&cof=BGC%3A%23FFFFFF%3BT%3A%23000000%3BLC%3A%230000CC%3BVLC%3A%230000CC%3BALC%3A%230000CC%3BGALT%3A%23008000%3BGFNT%3A%23000000%3BGIMP%3A%23000000%3BDIV%3A%230000CC%3BLBGC%3A%23FFFFFF%3B&sitesearch=wetwebmedia.com&biw=944&q=echinothrix+calamaris&btnG=Search Asthenosoma varium: http://www.google.com/custom?hl=en&lr=&ie=ISO-8859-1&cof=BGC%3A%23FFFFFF%3BT%3A%23000000%3BLC%3A%230000CC%3BVLC%3A%230000CC%3BALC%3A%230000CC%3BGALT%3A%23008000%3BGFNT%3A%23000000%3BGIMP%3A%23000000%3BDIV%3A%230000CC%3BLBGC%3A%23FFFFFF%3B&sitesearch=wetwebmedia.com&biw=944&q=asthenosoma+varium Asthenosoma ijimai: http://www.google.com/search?hl=en&lr=&biw=944&q=asthenosoma+ijimai Astropyga radiata: http://www.google.com/custom?hl=en&lr=&ie=ISO-8859-1&cof=BGC%3A%23FFFFFF%3BT%3A%23000000%3BLC%3A%230000CC%3BVLC%3A%230000CC%3BALC%3A%230000CC%3BGALT%3A%23008000%3BGFNT%3A%23000000%3BGIMP%3A%23000000%3BDIV%3A%230000CC%3BLBGC%3A%23FFFFFF%3B&sitesearch=wetwebmedia.com&biw=944&q=astropyga+radiata diadema savignyi: http://www.google.com/custom?hl=en&lr=&ie=ISO-8859-1&cof=BGC%3A%23FFFFFF%3BT%3A%23000000%3BLC%3A%230000CC%3BVLC%3A%230000CC%3BALC%3A%230000CC%3BGALT%3A%23008000%3BGFNT%3A%23000000%3BGIMP%3A%23000000%3BDIV%3A%230000CC%3BLBGC%3A%23FFFFFF%3B&sitesearch=wetwebmedia.com&biw=944&q=diadema+savignyi&btnG=Search diadema setosum: http://www.google.com/custom?hl=en&lr=&ie=ISO-8859-1&cof=BGC%3A%23FFFFFF%3BT%3A%23000000%3BLC%3A%230000CC%3BVLC%3A%230000CC%3BALC%3A%230000CC%3BGALT%3A%23008000%3BGFNT%3A%23000000%3BGIMP%3A%23000000%3BDIV%3A%230000CC%3BLBGC%3A%23FFFFFF%3B&sitesearch=wetwebmedia.com&biw=944&q=diadema+setosum&btnG=Search You have quite a lot of reading ahead of you! Cheers - Ted> 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>

Calcium and Urchins 1/11/05 No sea urchins in the tank I find them to be quite destructive on the corals. <this is a common and mistaken reputation of urchins because the wring urchins are usually purchased (rock boring short spine species, pencil urchins, etc.). The best Urchins are Diadema... totally reef-safe, nimble, do not eat much or any corallines, superb algae grazers, etc> So what in you opinion is the best type of calcium to dose with, excluding calcium reactors... <common calcium hydroxide... its time-tested and true with more benefits than any other form of calcium. Read more about it in our archives at wetwebmedia.com> had a bad experience with them once.. do not what to have that again. <its sounds like you knee-jerk react too easily my friend. Just because you've been given bad advice about urchins and calcium reactors, doesn't mean they are bad themselves. Calcium reactors are the single best and most reliable way to dose calcium and raise alkalinity in reef aquaria> Bryan <best regards, Anthony>

Re: Calcium and Urchins 1/12/05 Antoine to JamesG To help a bit on that question and for your future reference, mate... your urchin guess was a bit of a long shot, Most urchins are quite useful (critical on the reefs for algae control and  useful in aquaria). A few of the mismarketed species are cheap and abused... pencil urchins lean carnivorous (grazing benthic animal matter more than algae), and a few of those short spine black urchins (Echinometra and the like) are rock boring! And yes... graze corallines. But a bevy of others are very useful and reef safe... not the least of which is Diadema for tanks big enough to let one grow out. Their problem is/was lack of corallines though... and one great, reliable solution is Seachem's liquid calcium (polygluconate). It is... heehee... useless for coral growth IMO, but (!) it is simply outstanding for growing coralline algae rapidly. You have my promise that most aquariums that gets a 3 month dose of this cheap calcium will be swimming in calcareous algae! FWIW Anthony :)

Eating sea urchins Sorry I searched all over----just want to know how to tell if a sea urchin   is poisonous ( to eat)---I have found several recipes on how to prepare but have  been told some are toxic. << Good question.  Yes they are edible, and many dishes are made with them.  But yes they are poisonous.  You're the first person to bring this to my attention (can't believe I never thought of that before).  I wouldn't think their is much preparation involved in cooking them.  Best person for this is Bob, I'll pass on this email to him. >> Living on sailboat in western Caribbean--   Respectfully, Carolyn << Blundell- jealous as he lives in a laboratory in the western US >>

Toxic sea urchins Sorry I searched all over----just want to know how to tell if a sea urchin   is poisonous ( to eat)---I have found several recipes on how to prepare but have  been told some are toxic. Living on sailboat in western Caribbean--   Respectfully, Carolyn <Am not aware of any echinoids that are toxic to ingest (Uni, their eggs), though there are some that are dangerous to touch... e.g. the family Toxopneustidae. Bob Fenner>

Urchin Spines (10/3/04)) Thanks Steve. The orange thing is on the top. I assumed it was an eye because it moves around like it's looking at everything. <That part is the anal sac. Urchins have light-sensing organs that are not true eyes (with pupils & such, like fish do).> It's in a forty gallon tank. If my fish are stung will they die or will they be stunned? <I would expect a smaller fish to perhaps die, but it is not really likely that a fish will run into it, unless startled. I am not aware of reports of this urchin killing fish. Hapless aquarists have been injured. Thos spends (if we're really talking Diadema) get really long (>6"). I really think you ought to consider Mespilia globulus as an alternative, although getting that Diadema back out could be tough.> I have a Percula clownfish, a green Chromis, Firefish, scooter blenny, some polyps and a Kenya tree, along with some crabs and snails. <Sounds nice.> Will it be okay to keep or should I get rid of it, with what I currently have? <The maximum size of the body is about 4" and the spines can grow up to a foot long. I would not want one in a 40G tank if it was mine.>

Urchin Question (10/4/04) Hello! <Hi! Steve Allen with you tonight.> I have a question about a purple urchin. <Do you know the scientific name, purple is a rather common color among urchins.> I recently got him and he used to cruise all over the tank. Now I notice he keeps falling off the walls and he ends up upside down then I have a hard time getting him latched on again. <this is worrisome. They usually adhere firmly.> I have to prop him up but his spines keep him from being flush with the tank on the underside. Is he sick? I am thinking he's malnourished cause I don't feed him anything separate. I feed flake food and frozen krill and I also have some type of algae in the tank that floats around and is also starting to attach to a rock I have. <Do you have coralline? Urchins eat algae off of rocks.> Is this enough food? <Most urchins eat detritus and usually do not require supplemental feeding unless the tank is incredibly clean.> I read that you suggest that stuff from the oriental food place, is there anything else that I can buy in a regular store? <I'm a big fan of Sea Veggies for tangs and other herbivores. Spirulina wafers might work.> Thank you for your help. My urchin will be grateful!!! <Hope this helps. You can try these feeding options, but I'd also recommend checking all of your water parameters and making sure that you keep steady, ocean water chemistry. Echinoderms to best with pH and SG at normal seawater values and very stable.>

Sea urchin tests Dear Mr. Fenner, first I may introduce myself: my name is Willi Clarenbach and I am a German sea urchin test collector living in Haan near Cologne. If a learned from your internet sites you have had already contacts with at least one other collector (Royston Koh from Singapore). My question is, if you have a list available for selling and/or trading. To see my in the moment yet smaller collection please have a look on my internet site www.clarenbach.org and the link my echinoids. Please mail an answer. Many thanks in advance! Willi Clarenbach   <I don't have such a list, but do have sophisticated friends who may well know folks that do. Have cc'ed my "shell nut" friends here in hopes they will respond to your query. And we'll all be diving together in HI soon! Bob Fenner>

Echinoids Dear Bob, <Royston> Please let me introduce myself. My name is Royston Koh, an echinoids collector from Singapore. I recently surf your website at http://www.wetwebmedia.com/urchinsii.htm and found many pictures of echinoids. <Yes... easy to photograph... Ha! Wish you could have been at the IMAC conference this past weekend in Chicago... one of the vendors sold only fossil crinoids!> I wonder if you sell or trade echinoids test. I am interested in several echinoids species from your website. Please advise me.   Looking forward to hear from you soon. Thank you very much. Kind regards, Royston <Don't collect them per se... alive or already "clean", but do have some of the local (S. California) species. Bob Fenner>

Re: Echinoids Dear Bob, <Royston> Thanks for your kind and fast reply. I have collecting recent echinoids test for several years. I have over hundred of species in my collection and would like to trade/purchase for recent echinoids test (clean) from your area and others which you may have for spare. <You know I should have mentioned my good friend Marty Beals of Tideline... have you bought from them before?> I am interested from your website on the following species (bold color represent species with higher interest): Asthenosoma varium Chondrocidaris gigantea Diadema paucispinum Tripneustes ventricosus Microcyphus rousseaui Astropyga magnifica Strongylocentrotus sanfriscanus Diadema antillarum Echinometra viridis Lytechinus variegatus Meoma ventricosa Clypeaster subdepressus Strongylocentrotus purpuratus I collect mainly the test for collection and helping with my friend on the preparation of a book on sea urchin test. I appreciate very much for your help. I hope the specimens to have apical disc intact. If you have local species from your area which is not mentioned above, kindly inform me. <Ahhh!> I attached my Recent Echinoids Exchange List below: Recent Echinoids with perfect Apical Disc intactOrderFamily Genus and species Author and yearCountryArbacioidaArbaciidaeArbacia incisa(A.Agassiz, 1872)MexicoArbacioidaArbaciidaeCoelopleurus maillardii(Michelin, 1862)TaiwanArbacioidaArbaciidaeCoelopleurus undulatusMortensen, 1934TaiwanDiadematoidaDiadematidaeDiadema setosum(Leske, 1778)IndonesiaDiadematoidaDiadematidaeCentrostephanus rodgersii(A. Agassiz, 1863)AustraliaEchinoidaEchinidaeEchinus esculentus(Linnaeus, 1758)EnglandEchinoidaParechinidaeParacentrotus lividus (Lamarck, 1816)Adriatic SeaEchinoidaParechinidaePsammechinus miliaris (Muller, 1771)FranceEchinoidaEchinometridaeAnthocidaris crassispina(A.Agassiz, 1863)JapanEchinoidaEchinometridaeEchinometra mathaei(Blainville, 1825)Philippines and MauritiusEchinoidaEchinometridaeHeliocidaris erythrogramma(Valenciennes, 1846)AustraliaEchinoidaEchinometridaeHeterocentrotus mammillatus (Linnaeus, 1758)PhilippinesEchinoidaEchinometridaeHeterocentrotus trigonarius(Lamarck, 1816)MauritiusEchinoidaToxopneustidaePseudoboletia indiana(Michelin, 1862)AustraliaEchinoidaToxopneustidaeToxopneustes pileolus (Lamarck, 1816)ThailandEchinoidaToxopneustidaeTripneustes gratilla(Linnaeus, 1758)Thailand TemnopleuroidaTemnopleuridaeAmblypneustes pachistusH.L.Clark, 1912AustraliaTemnopleuroidaTemnopleuridaeAmblypneustes pallidus(Lamarck, 1816)AustraliaTemnopleuroidaTemnopleuridaeHolopneustes porosissimusL. Agassiz, 1846AustraliaTemnopleuroidaTemnopleuridaeSalmacis virgulata(L. Agassiz, 1846)ThailandTemnopleuroidaTemnopleuridaeTemnopleurus toreumaticus (Leske, 1778)SingaporeSpatangoidaBrissidaeBrissus (Allobrissus) agassiziiDoderlein, 1885AustraliaSpatangoidaBrissidaeMetalia angustus De Ridder, 1884AustraliaSpatangoidaLoveniidaeBreynia desoriiGray, 1851AustraliaSpatangoidaLoveniidaeEchinocardium cordatum(Pennant, 1777)FranceSpatangoidaLoveniidaeLovenia elongataGray, 1845SingaporeSpatangoidaSpatangidaeMaretia planulata(Lamarck, 1816)SingaporeSpatangoidaLoveniidaeEchinocardium mediterraneum Forbes, 1844ItalyClypeasteroidaArachnoididaeArachnoides placenta(Linnaeus, 1758)SingaporeClypeasteroidaFibulariidaeMortonia australis(Desmoulins, 1835)Northern Mariana IslandsClypeasteroidaFibulariidaeEchinocyamus pusillus(O.Fr. Muller, 1776)Tirrenian SeaClypeasteroidaFibulariidaeFibularia (Fibulariella) acuta(Yoshiwara, 1898)SingaporeClypeasteroidaLaganidaeLaganum retinens KoehlerSingaporeClypeasteroidaLaganidaeLaganum laganum(Leske, 1778)Philippines Please let me know if we can exchange recent echinoids test. Thank you very much. Kind regards, Royston <I am sending your note along to Marty and some other friends that may be able to trade with you. Good luck. Bob Fenner>

Recent Echinoids Dear Bob, Thanks for your reply. I do not know Marty Beals of Tideline. It will be nice to know them.  Are they shells dealer from California who took over the business from the late Mr. Bob Foster? <No... Marty (and former partner Dennis Mok) are owners/operators of Tideline (in Los Angeles), selling general and specimen shells and related artifacts> Regarding my exchange list of recent echinoids, appreciate if you can send to your friends who have interest in recent echinoids. <Have done so> I look forward to hear from you and your friends. If you obtain South California's recent echinoids from your dive, perhaps you can offer them to me. I can either purchase or trade depending on your preference. I can also use sea shells to trade for your urchins too if you are interested in shells. <Great> Beside the regular urchin and sand dollars, there are many heart urchin (Spatangoids) which I need from South California. Example: Spatangus californicus, Lovenia cordiformis, Brisaster townsendi, etc.. I really hope you and your friends can help because I need many good specimens for the preparation of the urchin book. <Will email them again> Thank you very much. Kind regards, Royston <Bob Fenner>

Sand Dollars (3/28/04) Hi, <Hi. Steve Allen tonight> I live in Jacksonville, Fl. and picked up (2) live sand dollars at the ocean. <Bad idea. Can you put them back?> I was wondering if these would be okay in a 55 gal. aquarium. <No. Even with a deep, live sand bed, it is virtually impossible to keep sand dollars alive in an aquarium. The odds that they will die in your system are over 99.9%.> Thanks, Dwight <Please put them back if you're close to the ocean.>

Urchins and Mantis Shrimp in LR (3/5/04) Hello guys <Steve Allen tonight> Hey thanks for all the help I need it! <We all do.> My son just stopped by to see my new reef tank and told me that I need to rid myself of all the black urchins in my tank. <Did he say why?> They came in with my live rock. Are they a problem in a reef tank? <What sort of "black urchin" are you referring to? Diadema species? Read here about urchins: http://www.wetwebmedia.com/urchins.htm The biggest problems are their venom, their occasional knocking over of live rock, and the possibility that they might eat all of your coralline algae. Read the articles and the FAQs and you ought to be able to decide what you want to do.> Please tell me what's so bad about Mantis Shrimp I guess I have a lot of them too! <Have you seen them? Here's a starting point where you can learn all about the problems people have with these aggressive, voracious predators: http://www.wetwebmedia.com/marine/inverts/arthropoda/stomatopods/mantisshrimp.htm > Thanks Kirt <Hope this helps>

Long spined sea urchin... excellent algae grazers 2/11/04 I just bought a long spined sea urchin a couple of days ago.  I was told at the pet shop that they eat algae off the glass of the aquarium and fine particles in the sand.   <they were exactly correct> Now I have been reading on the internet that it was in the past common practice for divers to kill sea urchins because of the negative effect they have on the reefs.   <not exactly... urchins are direly needed for reef health (as evidenced by the struggles of the Caribbean and other reefs without them). The only reference I can think of is in reference to the stupid practice of fisheries (for kelp) killing them. But that was for $/commerce... not reef health> I have a small amount of live rock in my 75 gallon aquarium (about 15lbs) Would I be wasting my time getting anymore?   <few are needed. Stick with what you have likely> I have been getting live rock a little at a time when I see neat pieces.  My last question is, will starfish destroy a reef tank too? <depends on the starfish... brittle and serpent stars are safe... most others are not. Read more about them here on our website and in our new book "Reef Invertebrates" by Calfo and Fenner. Anthony>

Urchin saves the day - eating Dictyota 2/2/04 Hello again Anthony, I wanted to give you an update about our Dictyota problem. Our urchin is now eating it. :) <outstanding to hear. I do love those urchins> We could not be more happy to see the right upper half of the tank free from this plague. Slowly the little urchin is going to town on it. Mark took a picture of the urchin to the SeaBay meeting but he never got the chance to show it to you. <Awww... no worries. DO send it here if you like> We are now sure it must be a long spined urchin. I hope he keeps up eating the Dictyota. If it eats all of micro algae will it be happy to eat any coralline algae? We don't want it to starve. <hmmm... tough to say. If so, I don't think it will survive on it. Fortunately, they will scavenge food bits. Offer an algae based frozen food and likely it will be fine (2-3 times weekly) after the nuisance algae is gone> Sincerely, Clair & Mark Dawson <best regards, my friends. Anthony>

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>

Urchin Compatibility (1-13-03) I was wondering if I could add a few little sea urchins in to my tank with an emperor angel, orchid Dottyback, a green chromis,3 cleaner shrimp and a chocolate chip starfish?  are all these compatible?<You should be ok, but I would probably only add one depending on the size of your tank.  You can read more on these guys at our website www.wetwebmedia.com.  Cody>

Sea Urchins Or? 1/12/04 Greetings Most Informative Wet Web Crew, <Greetings Flo!> I've asked you a couple of questions the 2 years I've been in the hobby and gotten some excellent advice mostly through reading the information on the site and books you recommend- so thanks and kudos to all of you. <Glad to hear you have benefited, and I hope to build on that tradition.> I have a question about some critters in my 40 gallon tank.  I have no fish in there, just many small feather dusters, a few hermit crabs, and 1 snail. The tank has an overflow, sump, and skimmer.  I feed the tank once per day just a bit of marine flake food.  Because there is nothing in it, I haven't scrubbed the algae off the acrylic tank for weeks and it has only a hard green algae on the sides.  I do change 5 gallons of water every week or so. <Wow!  Such patience.  I am already thinking ahead that you must have an amazing variety of critters enjoying a predator free environment!> In addition to this, there are about a million- maybe an exaggeration (probably more like hundreds or thousands) of little white colored things in my tank.  They seem to be all over the acrylic and the live rock.  I may have put some new live rock in the tank about 3-4 months ago and if I did it would have been a small piece (can't remember as I was prepping my new 100 gallon and mixed around some things).  I have about 45 lbs of live rock that has been in the tank over a year.   They are not brittle stars, I believe, as brittle stars have a central disk with arms coming out just on the sides.  They are not copepods as copepods can move quickly and look like little bugs.  They have a round central part that is about the size of a pinhead.  They are all approximately the same size.  They seem to congregate on the areas where there is green algae stuck on the acrylic and rocks.  They have for lack of a better word "arms" looking like small thin straight but still mildly flexible threads coming out of their sides, top, and back, but not on the bottom which is the part stuck on the rock or acrylic.  They are too small to see much detail, but do not swim, and seem to move so slowly it is hard to tell they move from one place to another.   <There are a range of possibilities, but I would lean toward some kind of Foraminiferan.> As I have virtually nothing in the tank, I'll see what they turn into.  I was going to stock the tank, but now will wait.  I am curious as to what they could be, how big they could get, how to care for them, and what to feed them.  I've tried looking for pictures or descriptions that sound like them, and the closest thing I see are sea urchins.   <Baby sea urchins are a possibility.  You could have imported some spawn material (Our own Anthony Calfo imported Cassiopeia larvae into his greenhouse).  I too would be curious what they will grow out into, so please do let us know!> They resemble small white sea urchins.  Is this possible?  I want to get a picture but they are so small it doesn't provide a good representation of them and the algae on the tank makes it hard to get a picture.  Thanks, Flo <Sorry not to have a better idea of what you have.  Please don't be too surprised or disappointed if they just start disappearing.  Many tiny critters wax and wane and come and go in our systems.  Best regards and enjoy to amazing diversity of life that we have the benefit of keeping in our tanks!  Adam> -

Urchin in the House - Thanks for the reply. <My pleasure.> With respect to your sea urchin recommendation.  Are there any issues with having an urchin in my tank with my livestock?? black brittle star cb shrimp & cleaner shrimp two gobies two clown fish Fire Goby hermits and snails??? <Should do fine with all these.> Don't the urchins get big? <Some do, but usually very slowly. The one I recommended is short spined and not very large.> I've heard of them knocking over liverock, etc...? <Not to worry, the Tuxedo urchins are a fairly tame bunch. Cheers, J -- >

Doing the Fluoro Salsa.. or Was It a Rumba? >Good afternoon! For Bob Fenner and other marvelous WWM FAQ crew. >>Good day to yourself as well.  How goes it? >Recently, my full-spectrum (daylight) fluorescent tube had been out-aged and cannot be used for more. After that, I ask my assistant to buy a daylight tube (I know this is seems to be not wise, because handling an knowledgeable task without supervising can make a wrong choice and creates one more problem) but I haven't much choice, I'm too busy for my stacking homework. >>Understood. >So, when he go home and I see what type of lighting he bought, I see it's a little bit different from the previous one. The light wasn't white-colored, but rather violet hued and seems not too strong to support autotrophic organisms in my aquarium. For example, my two Tridacna derasa clam (sorry -- it's not Tridacna maxima, I realized the species shortly after sending you the email) still exposes their broad mantles, but I'm not sure if the zooxanthellae can tolerate another type of lighting. >>I like T. derasa myself, my friend. >Do you know the type of lighting and is it good for my clams? >>I'm afraid not, my friend.  What you would need is to look for the manufacturer's specifications on the bulb.  I am guessing that you may have what is called a "warm white" bulb, in which case it will be too high in the red end of the spectrum.  You should be better getting a "cool white" bulb, or better yet, possibly calling the shop where your assistant bought the bulb, tell them what you HAD, and ask if they have that same bulb. >And also for my intertidal urchin, Colobocentrus atratus who seems to love the atmosphere and always tries to creeps out of water. I'm afraid if they will develop air bubbles in their test cavity, and slowly dies. >>No, I doubt they would harm themselves in that way. >Should I constantly replace the urchin back to water or just leave it alone? >>As long as it cannot escape from the display completely (and get lost?), leave it alone.  They know where the water is (DOWN!), and will go back when they feel the need. >Thank you very much for previous helpful emails !!  Sincerely, Anargha. >>Alas, I, Marina, cannot take credit for those, but will offer that you are welcome all the same.  Marina

Purple Sea Urchin Hi! My LFS has a "purple sea urchin." How can I tell if it's the California type that won't survive in my unchilled system? <Good guest ion... I would first just ask them... likely they know, or the species name may have been listed on their invoice from the supplier (Strongylocentrotus purpuratus and S. sanfriscanus are coldwater Californians... Otherwise, as far as I'm aware there are no purplish tropical species (though some Diadema look very dark/purplish).> Also, I understand it likes Caulerpa (have a lot) but  how does it interact with a Trachyphyllia or Yellow Tang. There is a warning in Mr. Fenner's book about the latter. Thanks, David A. Bidwell (Big fan) <No positive interaction... but possible troubles with urchins cruising into a Trachyphyllia coral. Bob Fenner>

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

What urchin is this? 10/8/03 Dear Bob, <Anthony Calfo in his stead> I hope you are very fine,  I received your excellent book Reef Invertebrates last week.  Thank you so much for it, it is an aquarists best friend and destined to be a classic I am sure. <kind thanks for the strong endorsement... glad it serves you well> I popped over to my LFS to buy some new Fluorescent tubes and saw some urchins there. I am having a bit of an Hair Algae problem (phosphates are slightly high) so I figured lets get my self one of these critters and see what it does. <not a bad idea at all... some key urchin species are grossly under-rated in our trade/hobby for this purpose> So I picked one up, so far it has not touched any of the hair algae, but did have a soft spot for my purple coralline algae, the little that I had.  Any way I am trying to identify this critter, I know its from Indonesia and it looks very much like a Mespilia globulus, but I cannot see any blue on it, it also has this habit of carrying a lot of macro algae on its back like a decorator urchin.  Its round and has orange and black short spines with white tubular feet.  I do not have a digital camera so I cannot send in a photo. Do you think this guy could seriously add to slide in water quality? <no harm at all... but do consider a Diadema species (long-spines) instead for algae control. They are incomparable> I have a Majestic Angel in this tank that I certainly would not like to get uncomfortable.  The angel has been with me for a month (she was 2.5 inches when I got her, seems 1/2 inch larger now) She feeds well leaves the corrals alone and eats everything I give her.  The tank is only 50 gal much too small for the Angel but its her temporary home, I will put her into a large aquarium at the end of this year. Kind Regards, Jorell <no worries... the urchin is likely harmless, and just not the most helpful species available. Small pacific Diadema species are commonly available... do consider. Anthony>
What urchin is this? II 10/8/03
Hi Anthony, Thanks very much for your prompt reply.  I will take your advice, I just got your book out and found a Diadema on page 333.  I have not seen these guys here in Hong Kong, I will look harder. <Ah, yes... no worries. Diadema setosum and D. savignyi are very common in the trade/hobby. You should easily be able to get these from an Indonesian supplier> I think I will get rid on the existing one as it is feeding on my coralline algae, it looks very pretty though, but I bought it for a reason that it does not fulfill.  By the way, taking a look at it again the feet are half black with the ends white. Could this guy be poisonous (i.e. could it be a Tripneustes gratilla species?)   <I cannot say from the text description, my friend> how I wish I had a camera..., <do browse the Internet until then for pics and a species ID> he's now all over the glass, the guy is black with orange spines, he has a few white spines but only around this mouth, his feet are black with white ends about a third of the length of the feet. Sorry to be bothering you.   <no bother at all... shared admiration> I work from home and the tank is right besides me, cant resist.  Hope you understand and sorry again. Regards, Jorell <kind regards, Anthony>

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