Itty Bitty Diadema urchins?

[AndyL]

Originally Posted by Delphinus

I like the blue bits in between the black needles

That's not his eye buddy

[Delphinus]

I wasn't talking about that - I was referring to the blue shorter needles....

[AndyL]

ah yours must be a bit different from mine - mines got blue spots around his orange tookus.

[kari]

Do these things split like cucumbers? I remember having a large one long ago but now have two "Itty Bitty" ones.

[Delphinus]

I've never heard of that? You wouldn't think so on account of their shell ... could there have been a spawn (or hitchhikers)?

[Beverly]

These may sound like dumb questions, but what is the purpose of having an urchin in a reef? I know they will eat coralline algae and sometimes knock over corals, which makes me not want to keep one. Do they pest macroalgae as well? And why a diadema urchin as opposed to other urchins?

TIA

[kari]

Beverly,
Their purpose is to help one hone their attention skills. I've already moved up to Fire Urchin level .

[Delphinus]

Because they're kewwwwwwwwwwwwwwwwwl!

No seriously, they're neat. Sure they knock things over but so do snails, so .. not really anything different there. In fact, if there's one profound lesson I've learnt as I near the 10-year mark in the hobby... glue those dumb frags down. They grow better anyhow if the isn't a hint of a wibble at the base.

And yes they do work on pest algaes as well, although it seems different species have different preferences. I had this sort of fuzzy brown algae that was really tough in texture, blue tuxedo urchin cleaned it right up. And although it's a coraline muncher, thing is, they actually help spread the coraline by spreading the spores around. So you have new coraline popping up much faster IME. So it's not all bad.

I have a green urchin (looks little like a tuxedo type, but a little different) and it is doing a number on the bryopsis I have in that tank. I couldn't be happier. And it is *so weird* to see this thing up on the glass, picking off little bits of hair algae or whatever ... with its "belly button mouth" ... LOL.

And why a diadema? Just for something different I suppose. But they also don't have a habit of dressing themselves with rubble like the globular types do. (Actually I don't mind the habit of "decoration" .. it helps me get at the little bits that I ordinarily can't get at... a very helpful janitor!)

Also when I was in Hawaii the diadema's I saw there had an incredible blue sheen to them. I can't describe it and I'm not sure if it showed up in the pictures very well but it was very neat to see. Ever since then I've sorted wanted to try one of those as well.

I dunno, it's like other ornamental things. Like, why CC stars, someone once asked me why I have those. The answer is sorta simple, "they remind me of the ocean."

Hope that clarifies some of the madness...

Originally Posted by Beverly

These may sound like dumb questions, but what is the purpose of having an urchin in a reef? I know they will eat coralline algae and sometimes knock over corals, which makes me not want to keep one. Do they pest macroalgae as well? And why a diadema urchin as opposed to other urchins?

TIA