[Taras1]

I have a small short spined Atlantic urchin which seems to leave my inverts alone. Pencil or Mine Urchins however are notorious for munching on all sorts of stuff, including the algae you buy them for. Do your research and understand the ecology that these animals come from. Many of the inverts are opportunistic feeders; if they can't get what they usually eat, they settle for something else. That something else usually will be a prize coral.