Tuxedo Urchin: The Pincushion Urchin

The Tuxedo Pincushion Urchin (Mespillia globulus), also commonly sold as the Blue Tuxedo Urchin or Royal Urchin, is a highly desirable and effective member of the marine cleanup crew. This small, rounded sea urchin is striking, featuring a pattern of velvety-smooth, brightly colored bands—often dark blue, black, or red—between rows of extremely short, fine spines. Its appearance resembles a pincushion or a perfectly symmetrical globe, inspiring its various common names.

Native to the Indo-Pacific, the Tuxedo Urchin is highly valued by hobbyists for its voracious appetite for nuisance algae, especially filamentous green hair algae. Unlike many other urchin species, its compact size, reaching a maximum of about 3 inches (7 cm) in diameter, makes it suitable for smaller marine aquariums, with a minimum tank size of 20 gallons recommended.

It is a generally peaceful invertebrate and is known for its peculiar behavior of "decorating" itself by picking up and carrying small pieces of shells, algae, and detritus using its tube feet. This camouflage helps it feel secure, as it is primarily a nocturnal grazer.

Diet & Compatibility:

• Diet: The Tuxedo Urchin is a dedicated Herbivore/Algae Grazer. It is highly effective at consuming various nuisance algae, including green hair algae and diatoms, as well as grazing on coralline algae. In tanks with low algae growth, it must be supplemented with dried seaweed (Nori) attached to a rock or clip to prevent starvation.
• Reef Compatibility: It is considered Reef Safe With Caution. It will not eat corals, but its constant grazing and movement can cause it to inadvertently knock over unsecured coral frags or small rock formations. Ensure all rockwork and corals are firmly secured to the structure.
• Temperament: It is Peaceful and can be housed with other peaceful inverts and fish. However, it is sensitive and should not be housed with predatory fish such as Triggerfish or large Puffers that may try to eat it.
• Water Quality: Like all echinoderms, it is extremely sensitive to fluctuations in water quality, especially high nitrate levels and copper-based medications, which are lethal. The loss of spines is often the first sign of poor water parameters or starvation.

Quick Facts

• Scientific Name: Mespillia globulus
• Primary Common Name: Tuxedo Urchin
• Other Common Names: Blue Tuxedo Urchin, Royal Urchin, Pincushion Urchin, Globe Urchin
• Origin: Indo-Pacific
• Max Size: 3 inches (7 cm)
• Temperament: Peaceful (Active Grazer)
• Diet: Herbivore (Voracious Algae Grazer)
• Minimum Tank Size: 20+ Gallons
• Reef Compatibility: With Caution (May knock over unsecured items)