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>

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>

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 forameniferan.>
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>

Book: Sea Urchins of Australia and the Indo-Pacific
It's finally available!
Sea urchins of Australia and the Indo-Pacific
Ashley Miskelly
December 2002
180p.
soft cover
full colour throughout
ISBN 0 9577455 6 7
The first full colour book ever published on Sea Urchins of Australia and
the Indo-Pacific, this book describes and illustrates 85 of a known 220
species  that occur throughout Australia and its offshore territories. Most
of the species likely to be found from low tide to about 20m deep are included.
Discover the variety of sea urchins that inhabit Australia and the
Indo-Pacific as each sea urchin is described in a format that is not
over-scientific nor too simple. Beachcombers, naturalists, divers,
professional and amateur marine enthusiasts will all find this book useful.
Each species is described in detail and illustrated with a number of colour
photographs, showing, in most cases, the live urchin, and four different
views of the test
If you have previously ordered a copy, you do not need to do so again
regards
Patty
****************************************************************************
**********
Worldwide postage A$10 per order!
Bookshop: http://www.booksofnature.com
****************************************************************************
****************
This is a once-only mailing to people dealing with the study of sea
urchins. I am sorry to have disturbed you if you do not appreciate this
information
Dr. Patty Jansen
Bookshop: http://www.booksofnature.com
Publishing and info site: http://www.capricornica.com
Books of Nature
P.O. Box 345
Lindfield NSW 2070
Australia
phone/fax: 02 9415 8098 international: +61 2 9415 8098
E-mail: capric@capricornica.com or books@booksofnature.com
<Thank you for this notice. Will post on our root web. Bob Fenner, WetWebMedia.com>

Urchin
We have an urchin that has seemed to have come with the live rock that we bought.  It has been about 1 1/2 years since we purchased the rock, so it has been a while.  I cannot seem to tell from the pictures on your site what types of urchin it is.  It is a black urchin, the "needles" on it are long and skinny, and the very end of the tips are white.  Is this a white tip urchin, and is it poisonous?  Thanks so much!  <  Sounds like a long spine urchin (diadema antillarum) to me, and yes he is poisonous. Cody> 

Urchin ID
Hi WWM,
I was just hoping someone there could help me with the ID on this sea urchin. It was labeled a rainbow sea urchin  at the LFS. I didn't think I would have any trouble finding out more about it. This is one of the few items I couldn't find on your site, Then I couldn't find it on any site.  If you know what species it is could you give me a better knowledge of care, That is if it's different from all other sea urchins.
Thanking you in advance,
David
P.S. Love the site, I'm another daily reader.
<Mmm, don't know this common name. Have you checked through the few species and pix we have posted on WWM?: http://www.wetwebmedia.com/urchins.htm
Maybe your dealer has an invoice for this animal listing its scientific name. Bob Fenner>

Echinothrix calamaris- Venomous purple urchin (pic attached)
What type of urchin is this.  
<Echinothrix calamaris>
I recently bought it from my LFS and they said it was a short spine white tip.  
<OK... many common names <G>>
Can you tell me its scientific name and common name and any other info that would be useful to me. Venomous?
<it is indeed venomous/toxic to people. The spines are hollow and open at the tip. This species is an indiscriminate feeder on green and meaty matter. Actually fairly well-behaved in reef tanks but not recommended by me for casual aquarium use>
Thanks Terry Rickman
<best regards, Anthony>

Astropyga radiata
Dear Bob Fenner:
I am writing to you about the urchin Astropyga radiata.
<Okay>
We run a dive charter boat in Morehead City, NC. Yesterday I collected an urchin at 130' deep, 40 miles offshore and I now believe it is an Astropyga radiata. No one we know has ever seen this particular urchin around here before. At this particular wreck site there were 4-5 colonies of 10-15 urchins each. Huge groups of these large urchins.
<Neat>
We gave the specimen to Paula Whitfield with NOAA, but at first glance her colleagues don't seem to think it is unusual for these waters. (She is also still looking for a more positive ID).  
Our first guess was Astropyga magnifica: based on the book "Reef Creature Identification" by Paul Humann. However, the photo does not match, and the description of the adult is inconclusive. The Audubon Field Guide North American Sea Creatures does not have anything resembling this urchin in it.
<Don't know much re this echinoid... other than Humann's id you list>
However, after an Internet search which turned up your photo and description...my suspicion is that it is a Pacific urchin (radiata), and may have arrived here the same way the Lionfish got here 3 years ago. (We have Lionfish inhabiting our reefs and wrecks now).
<So I'm given to understand (groan!). Would be unlikely that someone would buy, dispose of two or more individuals of the Pacific congener... but a possibility>
Can  you positively ID the urchin you labeled as radiata in the photo here: http://www.saltcorner.com/sections/zoo/inverts/echinoderms/urchins/Aradiata.htm and here: http://www.wetwebmedia.com/urchins.htm
(Some other websites have the Astropyga radiata and magnifica photos interchanged, and I would like an absolute positive ID on the red-colored urchin from your photo).
<Unfortunately the saltwater corner site doesn't load>
I would appreciate any assistance you can give me.
Attached are 2 photos of the urchin I collected yesterday.
Thank you very much for your time.
-Renate, for Atlantis Charters
<... and can't locate your attachments. Please do re-send. Bob Fenner, just back from Indo... where of all things, spent an inordinate amount of time searching an urchin (Asthenosoma varium) at similar depths to make pix of a commensal shrimp (Coleman's) w/o success>

Re: Astropyga radiata
Dear Bob Fenner,
Thanks for your response. In the meantime the urchin has been sent to the
Smithsonian for positive identification.
Should it turn out that it is another invasive species, you will surely hear
about it.
<Thank you. I appreciate the effort>
I have uploaded photos of the collected specimen on our website:
www.atlantischarters.net
<I see it/them... do look like Astropyga radiata... sigh>
Hope you have better luck searching your next urchin...!!!
-Renate
<Thank you. Me too! Bob Fenner>

Sea Urchins
Dear Sir,
I am a graduate student working on the taxonomy of sea urchins in my locality. I have been looking for materials written about Philippine Sea Urchins but I have been unfortunate in finding them. On this regard, I am seeking for your help in terms of sharing me some of your literatures on sea urchins or a guide for me on where to obtain them.
Sincerely yours,
Geraldine Andas, Libron
<You need to develop a search strategy (for scientific literature on the topic)... and visit a library (or computer hook-up) that can get you to Biological Abstracts, The Zoological Record... Please see here re literature searches: http://www.wetwebmedia.com/litsrchart.htm
Bob Fenner>

Species and Group
Hello Sir Fenner!
<Hello>
Among the sea urchins I have collected are pencil urchins. I need to validate as to whether they are Eucidaris tribuloides or Eucidaris metularia or Heterocentrotus mammillatus. Another regular sea urchin that I have collected appears to be Tripneustes gratilla or Lytechinus variegatus but I don't have enough literature on such species. All of which have been gathered in my locality, Davao City, Philippines.
<As far as I know, all of these are to be found in Philippine waters. What little we have content and reference-wise on urchins is posted here: http://www.wetwebmedia.com/urchins.htm
Perhaps a literature search: http://www.wetwebmedia.com/litsrchart.htm
is in order. There are likely survey works on the echinoids that cover the area. Bob Fenner>
Geraldine

Update
I know that it might be in the least of your concerns but I would just want to update you on the development of my research. I have successfully identified the specimens that I have collected. I am going back to the sampling site to gather more specimens (with bigger and better containers this time). Thanks for your help. Our written report will be due this October. Wish me luck!
Geraldine Andas-Libron
<I do wish you luck. Very exciting. Bob Fenner>

Unidentified Urchin
Hi, Bob:
I recently couldn't pass up a beautiful "blue-dot pin cushion urchin" from my 
LFS. He is about 4" in diameter with blue dots which fluoresce. I was told 
the critter is venomous. 
I was wondering whether you've ever heard of such a creature, and if you 
could tell me, though I don't plan on touching him, just how venomous it is 
(i.e., death, pain, etc.)
Thanks for your ever-helpful advice. Marilyn
>>
Yes, there are many such colored species of sea urchins... and yes, they are venomous through their tube feet... but not very dangerous to you. Far more of concern are physical injuries from their sharp spines. Take care if you have to move one of these biological pincushions to utilize a net... and not lift it into the air (in other words, scoot the urchin into a container underwater...
Bob Fenner

My new red sea urchin
Hello Mr. Fenner:
I am a beginner aquarist who has recently setup a 55 gallon tank. The
biological filter is established and the water quality is excellent by all
of my tests (NH3, NO2, NO3, specific gravity, pH and water hardness). I am
inquiring about a recent addition to my tank. I currently have 3 Firefish,
1 blue damsel, and my new red sea urchin. I was told by the aquarium
supplier that it is a red pencil sea urchin that would assist in reducing my
tank algae, but it doesn't look like any of the pictures that I've seen. It
is a mottled red-purple-tan color, with short, dulled spines. There is a
picture of what it most closely resembles at www.coolmoose.org/fish.htm.
<Yeah... I make this almost assuredly out as a Eucidaris metularia... and yes, it does eat attached algae... but wouldn't have expressly sold/suggested this as a/the algae eater for this system...>
Anyway, my question is, it seems to have these white, squiggly looking
attachments partially covering its spines. These attachments are open at
one end, circular with fanned out filaments that crown the open end. Is
this some sort of parasite, or is part of the actual sea urchin? If it is a
parasite, how would I treat it?
<Wow, you've got good vision! This is part of the Urchin, no worries>
If I can provide any other information, please do not hesitate to ask. I'm
going to look for a good encyclopedia of marine fishes, invertebrates,
echinoderms, etc., to assist me with my questions. I just haven't found a
good one yet. Thank you in advance for your assistance.
<There are a few... not just one... (It would be a real bicep builder!)... Do check on the listservs, the www.WetWebMedia.com site's Links pages for input for reference works... If you have the funds, Scott Michaels "Reef Fishes" books are very nice, The Modern Coral Reef Aquarium for their first three volumes in English (a fish one is on the horizon) for invertebrates in captivity, and the Baensch Marine Atlases in three volumes as well... have all of these (and a few others) within arms reach. Bob Fenner>
Deborah H. Colella

Sea Urchin
Good Evening,
<And to you>
Two quick questions ....
1. I believe I have a small Sea Urchin in my 90 gallon, 2 month old tank. It came with the cultured live rock, it is as large as the end of your small finger, black, and has spikes sticking out all over. Hides all day and comes out at night. Seems to be growing quite a bit. Is this an OK resident? Can't seem to find much info on these things on the net.
<Likely fine. Please see: http://www.wetwebmedia.com/urchins.htm
Something like the Diadema shown?>
2. How do you feel about Activated Carbon, and how often should I change it? As usual I hear pros and cons. I have a TidePool Bio wheel sump system, with one tray of AC. Thanks for your excellent resources.
<Please read here: http://www.wetwebmedia.com/carbonfaqs.htm
You are welcome my friend. Bob Fenner>
John Kummer

Sea Urchins
Mr. Fenner,
I came across your website, and was pleased to find a site that could answer
many of my questions on sea urchins. I am researching the species,
Astropyga magnifica, for a project I am putting together and I am having
difficulty finding the complete classification, from kingdom to species. I
was wondering if perhaps you knew of a source where I might be able to find
this, and other information on this specific species, or if there was
anything you, yourself, could tell me. Any help that you could give me
would be very much appreciated.
C. K. Spengler
<Mmm... let's see
o ECHINOIDEA (merisiilit)
|--o PERISCHOECHINOIDEA
| `--o CIDAROIDA
| |-- Cidaridae*
| `-- Psychocidaridae*
`--+--o EUECHINOIDEA ()? [paraphyletic?]
| |--o DIADEMATACEA
| | |--o ECHINOTHURIOIDA
| | | `-- Echinothuridae*
| | |--o DIADEMATOIDA
| | | |-- Diadematidae
| | | |-- Lissodiadematidae
| | | |-- Micropygidae
| | | `-- Aspidodiadematidae 
Genus Astropyga is a part of the Family Diadematidae...
Bob Fenner>

LR-Hitchhiking Urchins & Other Issues(3/8/04)
  I was checking out my new live rock after dark last night and saw what appears to be a sea urchin. It was about the size of a small button, black and had dull spines running along the edges, but not all around like most sea urchins I am familiar with. It also had several long, thin black wispy tentacles coming off it and waving around. I searched this site as well as the internet and the closest picture to match I could find was of a Shield urchin, but the photo was not very clear.
1. Does it sound like a shield urchin to you, where can I find a photo, and if it is, could it be a problem for my tank. <Well, urchins don't have tentacles, so I have to wonder. Does sound like one. Likely not something harmful anyway. At this point, I'd leave it be. Watching these LR hitchhikers turn up is half the fun. Next time I set up a tank, I'm just going to leave only the LR in it for several months to see what happens. As for pix, all I can recommend is to search the internet for the term. Check out www.wetwebfotos.com too.>
  I have a 55 gallon, FOWLR , protein skimmer, 2 powerheads and an emperor  400 and right now all I have is a Ocellaris clown, 3 Chromis and a "scooter Blenny" which is as I now know a Starlet or starry dragonet and I am trying to keep alive as I was misled into thinking it would eat algae. I have a large copepod population and a refugium tank with more copepods thriving so hopefully  the dragonet will stay as healthy as he is now. He seems to be eating very well right now. <Good. Hopefully, this Scooter Dragonet will be fine. I believe that they are less difficult than Mandarin or Psychedelic Dragonets. Their smaller size means they don't need quite as much food.>
  2. What are the dragonet's chances if I keep up the pod population? <Quite good I'd say. Mine has been thriving and growing for several months now.> I live in Charleston, S.C. and have access to as many pods as I can find at the beach. <A self-sustaining population is best because you risk introducing pathogens when you add stuff form the beach.> I started a 15 gallon tub of circulated saltwater loaded with
sand  and shells and pods as well in my garage and hope to be able to
sustain a pod population there as well and transfer them to the smaller
refugium as needed. <Do take a look at one of the smaller CPR AquaFuge HOT refugiums. A wonderful product. You might have to give up the Emperor to fit it.> Will this work, keeping in mind parasites, water
conditions, etc.? I also have access to live food through the LFS. I know the chances of the dragonet's survival are slim to none, but is it mainly due to the food issues? <Yes, and I'd say it's not that bleak, especially if you can keep up the pod population.> I don't want to bring him back to the LFS as they were the ones to mislead about him in the first place and they might just turn around and sell him to some other unsuspecting victim ( though the real victim here is the dragonet) <Yes>, and I don't know anyone local with a reef system to give him to. I usually research my buys first, but was unfamiliar with the dragonet and was told it was a blenny <an unfortunately common error that educated dealers should stop making> which I was planning to buy anyways. The new sales guy at the LFS did seem a little
eager to sell the "blenny". I learned a valuable lesson on researching
before I buy and won't fall for that one again. <Good>
I plan on doing everything in my power to keep the dragonet alive and
fat, but is what I am doing enough? <Yes, consider the refugium> what about variety in his diet? <Your LR should sustain a sufficient variety.>
  3. One more question: I bought my clown ( Nemo- very original name!) about 3 days ago and he adapted well, no signs of stress, etc. He was
tank-raised so he seemed like a hardy choice. The problem is he literally spends his entire time swimming against  the current created by my maxi-jet 900 powerhead. Is this normal? <This is common in clowns. If no other concerns, should be OK.> He isn't eating well either. <Give him a few days to adjust.> will take some dried plankton, but not much, if any, as he seems to spit most of it out. he won't take frozen or other dried flakes <Try frozen Mysis. Also, he may take good quality pellets.> that I can see and he doesn't seem to be scavenging either. What's wrong? <Probably just adjusting to the new tank, but you should have quarantined him. I'm a little concerned that the quality of clowns seems to be going down, probably from over breeding due to the Nemo craze.>
  The water is fine for the standard ammonia, nitrites and nitrates, etc.  <We always prefer real number--some are less fine than others.>
and the fish seem healthy with no signs of injury or stress so I am at a loss to the Nemo's problem. <Give it some time. Research on WWM for the signs/symptoms of Brooklynella, marine velvet & ich.>
  Sorry for all the questions, and even though I have quite a few years in the hobby, you guys are the experts and I defer to your wisdom. <Well, some are more expert than others, but all have experience, learning and passion.> Thanks for all the help and many enjoyable and informative hours of reading your website. <You're welcome. Hope this helps.> Jean