The Rock Boring Urchin have a round black body covered with hundreds of uniform, grey-black spines. Typically found in the back reef, this night-dwelling algae cleaner is known to burrow small niches in carbonatic rocks to hide. The Rock Boring Urchin requires ample hiding places and sufficient room in which to forage in the home aquarium. It generally hides in caves during the day, though it may make a burrow in thick substrates. At night, it comes out to graze on algae, moving about by its suctorial podia that are aligned in five doubled rows.
The aquarium should include large amounts of live rock on which it can graze. Rock formations need to be stable and able to withstand the burrowing movement of the Urchin wedging itself in crevices. Rock Boring Urchins are generally solitary, but will tolerate others of its own kind.
They are sensitive to high levels of copper-based medications and will not tolerate high nitrates. Poor water quality will cause it to lose its spines.
If there is insufficient algae for it to graze on, the diet should be supplemented with dried seaweed.
The Rock Boring Urchin can be confused with the White Spot Urchin (P. gratiosa), the Rock Boring Urchin has a Round shaped body whereas the White Spot Urchin has an Oval shaped body.