Blue Tuxedo UrchinHow to Care for Blue Tuxedo Urchin written by Dave Burr The Blue Tuxedo Urchin is especially useful in reef aquariums because it will eat unsightly Green Hair Algae. At the same time it is one of the more attractive urchins. Behavior: The Blue Tuxedo Urchin is nocturnal and spends the night grazing while fish sleep. It will not hurt corals or invertebrates. Blue Tuxedo Sea Urchins will pick up bits of substrate, loose mushrooms or polyps, or scraps of