Aquarium Lava Black Exotic Moss Plant Porous Rock Cave Kit All water type Dragon Stone Style 10 Stones Aquarium Black Lava Rock 10 pieces 7-2 inches long, some smaller for more decor options Create Caves for your aquatic pets hiding and birthing places Perfect for Aquascaping plant moss rocks. Safe for all water types This lava rock is known for its porous and unique characteristics which make the perfect home for coralline, fish and many other sea creatures. aquascapes approximately 10-20 gallon focal point area