So before I realized that pencil urchins eat coral I got one. Hes been in the tank 2 years now and doing great. Though every once in a while he climbs on top of a kenya tree and tried to eat it. I usually move him away with ease. He wedged himself in a rock and ate some coral, i got him our but accidentally hurt one of his spines i think. He seems to be doing fine but has anyone else done this?