sea urchin

[parks]

I recently purchased a piece of rock with a urchin hitchhiking on it. It is mostly dark grey/black with white tips on the spines. It is pretty pointy but not like a pin (a little thicker). There are also little tinticles moving around between the spines...does anyone know what kind it is and if it is dangerious to a reef...If it is an algea eater it can stay but if not it may go.
Thanks,
Parks

[2wetfeet]

Sounds like a Slate Pencil Urchin. I never had any problems with them and they did a good job on the algae. Post a picture if you can.

[aLucidDream]

Not sure on exactly how dangerous it is to your reef, but i do know most people don't keep them because they will eat your coralline on your rocks.

[Travis L. Stevens]

most of the people i know dont keep them, not because of the corraline algae but because they are little mini-bulldozers and will knock rocks over on themselves or on other things, such as snails, hermits, and even fish or eels

[parks]

Sorry,
My wife has the digital camera and she is in Hawii. I looked for the slate pencil urchin. That was not it but you led me in the right direction. I found it on this page...
http://people.hws.edu/mitchell/cards01/LEI2.html
It is the white tipped urchin on that page....
thanks for your help,
Parks

[usafjapan]

yup,.......... sounds like an urchin to me!!!!!!!!!!!