Red Slate Urchin (Heterocentrotus mammilatus)

Max Size: 8 inches
Diet: Omnivore
Temperament: Peaceful
Reef Compatible: With Caution. May move corals and rocks.
Minimum Tank Size: 30 gallons

The Red Slate Pencil Urchin, also referred to simply as the Slate Pencil Urchin, sports an attractive reddish-tan body adorned with long, blunt, and solid spines that resemble pencils. These spines project outward in all directions, reaching lengths of up to five inches. Interestingly, this sea urchin earned its name not only due to its pencil-like spines but also because these spines were historically used as writing implements on slate boards.

These urchins possess a unique mode of locomotion facilitated by suctorial podia, allowing them to move gracefully. They exhibit enough traction to scale the glass sides of an aquarium with ease.

Given their substantial size, accommodating Red Slate Pencil Urchins in an aquarium necessitates a robust rocky reef structure. Care should be taken to ensure secure placement of rock pieces to prevent accidental displacement. While they can be detrimental to corals, they coexist safely in fish-only aquariums. Typically solitary creatures, it is advisable to house only one Red Slate Pencil Urchin per tank. Operating primarily during the night, they tend to conceal themselves during daylight hours, venturing out after dusk to graze on algae. Live rock serves as an excellent source for their dietary needs. These urchins favor environments with low nitrate levels and are sensitive to copper-based medications. Shedding a few spines is not uncommon, but an extensive loss of spines often indicates poor water quality.

In cases where there is insufficient algae for grazing, their diet should be supplemented with dried seaweed to ensure their nutritional requirements are met.