Boring Urchins

[ScubaSteve]

I had a Hawaiian rock boring urchin that came in as a hitchhiker and grew to full size. It bored itself a hole in one of my rocks but didn't spend much time there. The boring action is likely a response to predators, of which there are none in my tank.

[Magickiwi]

Looking forward to posting a couple pictures when I get home. With my waterproof point and shoot I couldn't get a wide enough shot to show the size of the colonies.

Needless to say this would not be a desirable behaviour in a reef aquarium.

[Aquattro]

Might be a different species, I saw thousands in Cambodia and they didn't bore into the rock.