The Pincushion Urchin (Tripneustes gratilla) or commonly referred to as Pincushion Hairy Urchin, Cake sea urchin, is one of many premium ornamental invertebrates, that are completely reef safe and will consume many types of unwanted algae on the rocks. The Pincushion Urchin has an oval to round body covered with hundreds of uniform spines and can be found among the Atlantic Ocean. Its color can range from red to purple to white and blue.
They reach a maximum size of 3-4 inches and will require ample hiding places and sufficient room in which to forage in the saltwater aquarium. During the day, it will hide among the rocks, in crevices, or under plants in a sandy substrate. At night, it will emerge to graze on the algae present in or near its home.