Green star polyps grow as soft mats covered in tiny star-shaped animals, and under aquarium lights they glow a green so bright it looks electrical. The Avocado Green Star Polyp has turned the lights down. This ceramic version spans 4.75 inches and sits 2 inches deep: a central star surrounded by smaller ones, glazed in an earthy, lived-in green. Mounted on one screw, it sits easily beside wood, linen and houseplants. It does not spread across the tank, because there is no tank.