Hairy Pincushion Urchin (Tripneustes gratilla)

Max Size: 4 inches
Diet: Omnivore
Temperament: Peaceful
Reef Compatible: Yes
Minimum Tank Size: 30 gallons

The Hairy Pincushion Urchin, also known as the Sea Egg and Priest-hat Urchin, features eye-catching patterns with five or ten double rows of white and red spines, separated by spaces of red, purple, white, or black. To blend into its surroundings, this urchin often covers itself with rocks, sponges, shells, or algae. This not only provides camouflage but also offers shade and sometimes serves as a food source. In aquariums plagued by filamentous algae, the Hairy Pincushion Urchin proves to be a beneficial addition, quickly consuming this unwanted algae.

To thrive in an aquarium, the Hairy Pincushion Urchin requires ample hiding places and a large area to move around. It prefers an aquarium with live rock, allowing it to graze on algae, including Caulerpa sp. It should be housed with nonaggressive fish to ensure a harmonious environment. Additionally, it is sensitive to high levels of copper-based medications, so care should be taken when using such treatments. Maintaining good water conditions is essential, as poor water quality may cause the urchin to shed its spines and experience a rapid decline in health.

Breeding the Hairy Pincushion Urchin in an aquarium is extremely challenging due to the lack of distinguishing characteristics to differentiate between males and females.

If there is an insufficient amount of algae for it to graze on, the Hairy Pincushion Urchin should be supplemented with dried seaweed to meet its dietary needs.