Common name: Pencil Urchin

General information

The Pencil Urchin, scientifically known as Eucidaris metularia, is a distinctive species of sea urchin found in tropical waters. It is characterized by its thick, blunt spines that resemble pencils, which is where it gets its common names. These spines provide protection and deter predators. The Pencil Urchin is a nocturnal creature, often hiding in crevices during the day and emerging at night to feed.

Care

In the aquarium, Pencil Urchins require a stable environment with plenty of live rock to graze on and hide among. They are generally hardy and can adapt to a range of water conditions, but they do best in well-established tanks with consistent water quality. It's important to ensure that the tank is free of aggressive fish that may attack the urchin's spines.

Reproduction

Eucidaris metularia reproduces by releasing eggs and sperm into the water column, where fertilization occurs externally. In the home aquarium, breeding is rare, but with optimal conditions, it is possible to observe spawning behavior.

Symbiosis

While not known for any specific symbiotic relationships, Pencil Urchins often provide microhabitats for small organisms like commensal shrimps and crabs, which may hide among their spines for protection.

Habitat

Pencil Urchins are found in a variety of marine environments, from shallow reefs to deeper waters. They are commonly found in the Indo-Pacific region, including the Red Sea, the Indian Ocean, and the western Pacific Ocean.