Coraline and Sea Urchins

[Seepu]

Another topic was talking about clean up crews.... and it was mentioned that Urchins will eat coraline algea.

I have one unidentified Urchin (almost 2 inches across, minus the spines), and about 160 lbs of LR in my 90g. I really don't want my rocks to be covered in coraline... I don't like the look of all purple rocks, but I would like to see SOME color. Will this Urchin eat TOO much coraline for me to have any at all, or is coraline something that it supplements its diet with?

 

[Fluff]

They eat some coralline but in my opinion, not really enough to notice. Your urchin looks like a pin cushion urchin.

 

[Seepu]

Thanks, Fluff!

Are their different colors or variations of 'pincushion' urchins? I Googled that, and saw some with black spines, some I thought were 'hairy' urchins (short spines, look furry), and something I thought was called a 'tuxedo' urchin (short-ish spines, dark and light contrasting 'bands'.)

Is 'pincushion' urchin a catch all name, like 'clown fish'?

 

[zenn]

I ended up with 3 urchins that hitchiked on my LR. 2 pencils and one purple urchin. They purple urchin eats coraline like mad. He really depleted some spots bad. And he grew super fast too. So i threw him and his pencil urchin buddy into the sump. Then i just found another one the other day in the main.

IMO, they eat too much coraline. But i wouldn't go so far to say they'll deplete your supply of it. I don't think that's possible. They might eat most of it but they'll never eat it all. FWIW, they keep my sump really clean:shrug:

 

[Fluff]

Your describing three different species. The species I'm thinking of is Tripneustes gratilla that live aquaria lists as hairy. But yeah, color is variable.

 

[Seepu]

Ok.. thanks again!