Long Spine Urchin

The Long Spine Urchin has an open, radiating outline that needs considerably more clearance than its central body suggests. It commonly shelters in rockwork during daylight and ventures out to graze algae when the aquarium becomes darker.

Provide securely supported rocks, shaded retreats, and sufficient algae-covered surfaces. Offer dried marine seaweed when natural grazing is depleted. An urchin should not be added to a bare new aquarium simply because algae may appear later.

Its sharp spines require a careful maintenance plan: leave room to work and never grasp or press against them. Do not assume spines make every fish a compatible tankmate. Maintain stable water quality, avoid copper-based medication, and investigate substantial spine loss promptly rather than treating it as normal shedding.