Common name: slate pencil urchin

General information

The Slate Pencil Urchin, scientifically known as Eucidaris tribuloides, is a species of sea urchin that is quite popular among reef aquarium enthusiasts. This urchin is known for its thick, blunt spines that resemble pencils or sticks of chalk, hence the name. It has a robust, globular body with a reddish-brown to dark purple coloration, which can add an interesting visual contrast to the reef tank.

Care

Slate Pencil Urchins are relatively hardy and can adapt to a range of conditions found in well-established aquariums. They are nocturnal and prefer to hide during the day, so providing ample hiding places is essential. These urchins are herbivores, grazing on algae and detritus, which makes them excellent algae controllers in the tank. However, they may sometimes feed on coralline algae, which some aquarists try to cultivate.

Reproduction

In the wild, Eucidaris tribuloides reproduces by releasing gametes into the water column, a process known as broadcast spawning. In the aquarium, breeding is less common, but with optimal conditions, it is possible to observe spawning behavior.

Symbiosis

While not known for a specific symbiotic relationship like clownfish and anemones, Slate Pencil Urchins can contribute to the tank's ecosystem by providing shelter for small creatures among their spines and helping maintain a clean environment by consuming algae.

Habitat

The natural habitat of the Slate Pencil Urchin includes rocky substrates and coral reefs in the tropical Western Atlantic, from North Carolina in the USA to Brazil, including the Gulf of Mexico and the Caribbean Sea. They are typically found at depths ranging from shallow waters to about 30 meters.