Warning regarding longspined urchins (Diadema sp?)

SevTT

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I got one of these recently, 'cause they're neat and I had hoped that it would mow down my bryopsis. In the week or so it was in my tank it managed to rub the flesh off of chunks of several acro frags with its spines (observed in action,) chew off a hunk of a montipora (possibly undata)(seriously, chewed a chunk off the skeleton. Not observed, but there's nothing else in my tank that I can think of that has jaws capable of that,) stripped the flesh off part of another montipora, (observed in action,) and I have a feeling that it also may have killed or help kill most of the other montiporas in my tank, through feeding actions or through poking them with its spines. (I -did- find monti eating nudis in my tank, but I haven't seen any of them in the tank or on the monti frags, during the day or at night, for about a week, and I think most of them have been consumed by new tank additions. A lot of the flesh loss doesn't correspond with the way that nudis eat the corals, either.)

Between this and the nudis, pretty much all of my montis are toast. A few of them show flesh in the polyp-holes, so I'm hoping they may pull a lazarus. All of my acros are damaged but they shouldn't have a real problem recovering unless they RTN or something.

This urchin was one of the types with a black/grey anal bulb, and thin, attractive, neon-blue stripes (not dots) that appeared to run along the places where the plates that make up the test join. It had the usual jet black, long, sharp-assed and venomous spines.

And the mother-fragging SOB didn't even freaking eat the bryopsis.

Did I get some kind of evil urchin species masquerading as a diadema?
 
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ryangrieder

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wow man that sucks! soooooo is it still in the tank? got a pic of the urchin so we know to make a note to not ever be interested in purchasing one? sorry about that man. hope it grows back ok
 

SevTT

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wow man that sucks! soooooo is it still in the tank? got a pic of the urchin so we know to make a note to not ever be interested in purchasing one? sorry about that man. hope it grows back ok
Naw, it's not in the tank any more, I tossed it into a 29 that I'm in the process of slowly breaking down but which is still fully functional at the moment.

Here's a crappy pic from when it was in the tank:

 

SevTT

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wow and hes only a little guy too that did all this huh? damn. id be using each spine as a tooth pic after he did all that to the coral!

All I can say is: thank god this tank was pretty much all populated with frags from the swap, and all of my monti frags were relatively cheap, so the financial loss was less than it could've been.

On the other hand, I'm -really- gonna be annoyed if the Montipora samerensis I bought doesn't pull through, 'cause that was just a really good-looking piece. :(
 

Dre

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It's a pitty you didn't ask fellow reefers about urchins before you bought it .They are indiscriminate eaters too man.They eat live rock and coraline algae as well.
 

Killerdrgn

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Yeah Urchins really chew through anything that has algae on it, but don't blame the urchin just yet because i've had a bout of monti eating nudibranches before and they do leave "bite" marks also.
 

Lionfish718

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Wow!!! You need to take it out. I have one, 6 inches wide and it mowed down my clove polyps as soon as I put him in the tank. It will destroy your tank.
 
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jaa1456

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Who told you that it will eat Bryopsis?? Whoever did told you a nice big fat lie. I would take it back and tell them I want my money back. Although they most likey won't do that.
 

scubabr53

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I have two pencil urchins, but I keep them in the sump with all the life rock and a few brittle stars. I learned my lesson in fast when they overturned few small rocks that caused my reef imitation construction to crash. Since than they both are residents of my sump (almost 2 years) grazing on life rocks algae. Now we all happy, well at least I am.
 

SevTT

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It's a pitty you didn't ask fellow reefers about urchins before you bought it .They are indiscriminate eaters too man.They eat live rock and coraline algae as well.
Well, I did a decent amount of research online and I didn't see anything out there saying that they'd eat corals. The only cautions I saw were regarding their spines and their tendency to knock frags over, both things I can live with or manage. *shrugs*
 

SevTT

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Yeah Urchins really chew through anything that has algae on it, but don't blame the urchin just yet because i've had a bout of monti eating nudibranches before and they do leave "bite" marks also.
No, I can definitely blame the urchin. :) I watched it pass over a piece of purple Monti cap and leave a stripped, white skeleton in its passing. And the other montipora looked like someone had rasped off about a quarter inch of skeleton with a rough file. Nudis just strip the flesh.
 

Audi0s

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I saw a mandarin at a tank at Abs Fish with a spine thorough its eye. Poor guy made it all the way to north jersey to get spined right in his face. Im sure this is a problem too for some people.
 

SevTT

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Who told you that it will eat Bryopsis?? Whoever did told you a nice big fat lie. I would take it back and tell them I want my money back. Although they most likey won't do that.
Well, the people at the LFS didn't tell me it eats Bryopsis; there're quite a few online sources, however, which state that they do. TBH, that was a relatively minor consideration; I mostly just wanted it 'cause I've always wanted one, and, since I didn't see anything online about them doing anything worse than bulldozing frags and stabbing reefkeepers, I figured why not? My tuxedo urchin has always been a model reef inhabitant and never harmed anything.

Aah well. Live and learn. Maybe I'll put the prefilter on my vortech and get me a few of the proper kind of lettuce nudis to clean up the bryopsis, if raising the mag and pH (as I am currently doing) doesn't help.
 

jaa1456

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You gotta use the Kent mag though. Tech M, and the lettuce Nudis won't be much help unless you get a ton of them. They eat about one strand a day and you know if you have bryopsis it grows faster than that.
 

SevTT

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You gotta use the Kent mag though. Tech M, and the lettuce Nudis won't be much help unless you get a ton of them. They eat about one strand a day and you know if you have bryopsis it grows faster than that.
Yeah. I was figuring that I'd get two, stick 'em in my sump or maybe a breeder box until they lay eggs, and then introduce the lot of 'em to the tank. Kind of the way you do it with Berghias for aptasia.
 

jaa1456

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There is a place near me that sells them for 5.00 per Nudi, lowest price I have seen. He had 150 of them and sold out in about 3 days. Said he has a new order coming though
 


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