The Hairy Pincushion Urchin, also known as the Sea Egg or the Priest-hat Urchin. With its unique appearance featuring rows of white and purple/pink spines, this urchin not only adds a touch of intrigue to your aquarium, but also serves as an effective algae control agent. Its ability to camouflage itself with rocks, sponges, shells, or algae helps it blend seamlessly into its environment while providing shade and potential food sources. Say goodbye to unsightly algae infestations in your aquarium with the Hairy Pincushion Urchin! They grow to about 4 inches in length and require a minimum tank size of 30 gallons. They are reef safe but have a habit of knocking over loose frag plugs so keep an eye on these little guys in frag tanks.