Sea Urchins in Reef

[Cheekymonkey]

Interested in

Pincushion Urchin, Blue Tuxedo
(Mespilia globulus)

I understand that they will grab small frags and put them on themselves, but should he cause any problems with large placed corals which are glued in place?

[ACBlinky]

I have a pincushion (quite large now), and he picks up shells, rubble, small frags and pieces of macroalgae, but he generally doesn't bother anything that's larger than an astraea snail.