Quote:
Originally Posted by Witfull  this is not unusual. urchins are bulldozing grazers. they scrape off whatever is in their path. |
Agreed with this. They will plow over rocks, and corals in their way. I would check the spines of the urchin, a few may be stuck to the urchin. I would be surprised also to see a yellow polyp or two floating around somewhere in the tank waiting to attach to something else. They scrape off very easily from glass.