Diadema urchin

[Ali A]

Hi all,
Bought this from Clearwater today after going to the WYMAG seminar, possible Diadema??

http://stardesk.staroffice.com/www/Ali_A/Dscf0020.jpg

atb
Ali



Last edited by Ali A at Oct. 28 2002,07:29

[will000]

hey nice pic + what is that thing on top it looks like an eye http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/biggrin.gif

cheers will http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/blush.gif

[Ali A]

errrr, I think that is its backside. http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/laugh.gif http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/laugh.gif http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/laugh.gif http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/laugh.gif
Ali

[Ali A]

Another shot of its backside..

http://stardesk.staroffice.com/www/Ali_A/urchin.JPG

Ali



Last edited by Ali A at Oct. 28 2002,00:05

[bunglehaze]

i got one of these too only I didnt realise it was a diadema urchin, got told it was a black mine urchin!
cheers for the elightenment and nice pic!

cheers
leigh http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/biggrin.gif

[Ali A]

Hi Leigh,
You could be right, as I was hurrying to beat the crush after the event so I forgot to ask the exact spp. (slipped my mind)!! Although apparently they had the little blighter from very small.
Ali

[mark]

Hi Ali

It is a Diadema i've had my eye on that one at Clearwater for a while but never got round to buying it. Seems i should have gone in on Sat because Suk got to the last Sea Squirt that was left to. http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/sad.gif http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/sad.gif http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/sad.gif

The Diadema Urchines arn't the rock boring ones so they shouldn't move the rock work in your tank. I've one of the Tucedo Urchine and it's doing a good job of keeping the algea in check. http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/smile.gif http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/smile.gif

Cheers

Mark.

[gman]

Yep it is a diadema.In fact im almost sure it is Diadema setosum.
Cheers Graham http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/smile.gif

[Ali A]

Thanks for the replies guys,

Mark, you snooze you lose http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/tounge.gif *http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/tounge.gif *http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/tounge.gif

Graham, thanks for the reference.

Heres a shot of its mouth, urgh!!!



cheers
Ali[img]http://stardesk.staroffice.com/www/Ali_A/Dscf0033.jpg



Last edited by Ali A at Oct. 28 2002,22:35

[gman]

Hi Ali
If you like I can give you some info on feeding and care.This I got from a marine biologist and expert on urchins in response to a question I and another reefer posted on reef central as regards feeding and care.Just let me know.
Cheers graham http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/smile.gif

[Ali A]

Graham,
By all means, fire away, any advice tips etc would be greatfully recieved.

The urchin has been quite active, scurrying about the place, munching on bits of corraline, and it even had a bit of seaweed today.

Cheers

Ali

[gman]

Ok Ali,Here goes.There is quite a bit of it.
In addition to the foods that Monty and Hawk suggested, another possibility is a bit of boiled egg. Yes, you read that right - we actually feed the urchins we use for our research here at UCD on bits of boiled egg. Just a small piece (depending on the size of the urchin: something on the order of a pencil eraser for a quarter-sized urchin) of the boiled egg white (no yolk!http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/wink.gif about once a week or so really helps to keep them healthy and growing well. If your urchin seems to be healthy otherwise, that should be enough food to keep it thriving in your tank for years to come.
Just another thing to keep in mind. If it really is Diadema (as opposed to one of the dozens of look-alike urchins), their spines can be quite nasty, and some people react badly to their toxin. Some species of Diadema (e.g., D. antillarum) can also get quite large (basket-ball sized including the spines), so this animal may get too large for the average aquarium eventually. Hopefully you have one of the smaller species, or a Diadema look-alike (such as Echinothrix calamaris) which tends to stay much smaller...
Rob
[ then, it's mostly guessing at the most likely candidate for the majority of species. To be confident about an ID for something, you really need to have it in your hand. Having said that, I'd guess that the bright orange ring at the top is likely to point at Diadema setosum for Debi's urchin, and the fluorescent blue on the back, coupled with the banding on the spines suggests that you're likely to have Diadema savignyi, Graham, but I can't find a decent close-up picture of one of these guys on the web for you to compare with. D. setosum is the one that is most often recommended for the reef aquarium, but the bottom line is that all of these urchins are omnivores, rather than algae specialists. It is true that most of the diadematoid urchins feed primarily on algae as juveniles, and although none of them will do much with long filamentous green algaes, they can do a pretty good job of controlling some fleshy macroalgae and surface growth of diatoms (although they won't likely eat any dinoflagellates or cyanobacteria, either). Sadly for us as aquarists, as they mature, virtually all of these animals switch over from feeding primarily on algae to preying primarily on invertebrate prey. Some prefer small cnidarians and sponges (such as you're seeing, Debi), while others feed primarily on carrion (the occasional dead fish or shrimp, etc.), and others feed primarily other urchins or sea stars (such as the "wolfpack" urchins Lytechinus that often swarm larger urchins to consume them). For what it's worth, Debi, D. setosum is considered one of the least predatory of the diadematoid urchins, and most of the others have a taste for much more animal flesh than the one that you have. In general a bit of boiled egg-white, a mussel on the half shell, or a bit of prawn or squid a couple of times a week should curb their habit of eating your inverts. If this one turns out to be a real terror for your reef, you can always still take it back, but it doesn't take much effort to feed them (just drop the food among the spines on the top of the urchin, and they'll move it around to the mouth on their own), and it may change the animal into an addition that you actually like Numerous studies have now shown that the grazing activites of these urchins on natural reefs increases the percentage of coralline algae cover. This happens because of two things - first, they are messy eaters, and like the scraping suggested by Monty, the urchins release a lot of coralline algae propagules when they graze on it, and spread the algae around. Second, they prefer a wide range of other algae and invertebrate prey to coralline, and if there is something else available, they always switch over to feed on that other food instead, leaving the coralline to grow. If one of these urchins is wiping out your coralline algae in an aquarium, then two things are likely true: 1) the urchin is starving, because coralline algae is generally their last resort food (other than the filamentous greens, cyano and dinoflagellates I mentioned that they avoid above). Debi, if you bought the urchin to control one of these avoided algae, it's not surprising that you are unimpressed with their algae eating habits. 2) The tank is too small for an urchin of the size that you have. This is really a combination of 2 things - bigger urchins eat more, so they do more damage, and without sufficient space to graze, they will move over the same spot multiple times before the coralline has a chance to regrow. The more they eat, and the more often they move over the same spot, the less likely the coralline will be able to keep up with the grazing of the urchin. You're hit with a double-whammy here, though, because the urchins also gain a substantial taste for animal flesh as they grow larger, and that means trouble for the reef critters (not so much of a problem for your fish-only tank, Graham), and also that the urchin will grow even faster... All-in-all, these animals are best left to very large reefs, or fish-only tanks, such as Graham has, provided that you are willing to keep the animal fed properly... Rob Posts: 827 | From UC Davis, California, USA | Registered: Jul 99 | IP: Logged

Hope this helps Ali
Cheers Graham http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/smile.gif

[Ali A]

Graham,

Egg White?http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/confused.gif WTF http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/laugh.gif http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/laugh.gif I'll have to try that one, I've just told my girlfriend and she pi$$ed herself laughing.

It's mainly been in the corner behind one of my powerheads for a couple of hours. I think It wants a bit of peace and quiet because my Fireball Angel has taken quite an interest in it.

Tanks for the info!!
Ali

[bunglehaze]

hmmm I dont see any colour on my urchin! does this mean it is not a diadema? also it is pure black with the occasional white spine, even the mouth area is jet black.

any ideas?
cheers
leigh http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/biggrin.gif

[GhostsForge]

Was about to take mine back to Clearwater as it is geting a bit large.

Inherited it on a piece of rock when its spines were less than half an inch, now its spines are between 4 and 5 inches

Is it worth keeping?

Thanks

GF

[gman]

Ali
I tried mine on the hard boiled egg white and it worked.It used to prefer nori though.When it was stuck on the the glass after lights out,I would put a piece of nori in a lettuce clip next to it and he would be on it straight away.not too sure about them in a reef.But it did a bloody good job on the algae
in my fowlr.Hence my request for feeding info.It was running out of grub.
Cheers Graham http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/smile.gif

[gman]

Ghosts forge
You pays your money and takes your choice.As it says in the article,pretty hard say what species it is.If its not causing you any grief and keeping the algae down,I would leave it.
Cheers Graham http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/smile.gif

[Ali A]

Wow,

Just take a look.....

http://stardesk.staroffice.com/www/Ali_A/urchinnegg.JPG

Thanks again for the info Graham, the little blighter devoured the egg in about the time it took for me to take a pic, download it to my puter, then to the net and then to post here http://www.ultimatereef.net/ibv3/iB_html/non-cgi/emoticons/smile.gif http://www.ultimatereef.net/ibv3/iB_html/non-cgi/emoticons/smile.gif http://www.ultimatereef.net/ibv3/iB_html/non-cgi/emoticons/smile.gif .

Its no yolk.

Ta
Ali