advice needed urgent.

[kari]

If its the typical black spiny urchin, I agree with Steve. These guys grow very fast and eat coraline very fast. From what I have noticed, they clean off the algae right down to bare rock very quickly. I've been trying to bag mine for quite some time. Mostly nocturnal in activity in my tank.

I haven't witnessed any problems with them other than the occational spine in the finger