Scientific name - Tripneustes gratilla Family – Diadematidae Common name – Hatpin Urchin Max Size – 3 in (9 cm) Range: Indo-Pacific Care Level – Moderate Temperament – Peaceful Foods and feeding – It will roam the aquarium eating algae Aquarium suitability - Reef compatibility – Yes Captive care – This urchin can be a very helpful member of your CUC. They do best in larger aquarium with plenty of area for them to roam. They will pick up anything that is not glued down to camouflage themselves. Like all invertebrates it is extremely sensitive to nitrates and copper, and small amount are fatal to it.