Orange spine urchin?

[M0oN]

I've got a baseball sized short spine orange pincushion urchin and I'm wondering if it's a bad candidate for a reef tank - I've noticed a significant decline in my coralline algae since adding him in, and he's constantly knocking things over.

Is this a bad choice - recommendations? Should I trade him in for a tuxedo?

Orange, white, and black on him...short spined...

http://pieckiel.com/images/Dive/Dive web072.JPG

 

[MartinEric]

He looks like the Tripneustes Gratilla: http://www.liveaquaria.com/product/prod_display.cfm?c=497+530+594&pcatid=594

If so should be ok. If you can handle the knocking things over that is.