Made of non-toxic resin. Features an aged rhino skull with sharp horns. Designed for both fresh and salt water aquariums. Perfect place for your fish to hide and play. Dimensions: 3.5Lx 6W x 5H in. Can your aquarium get an cooler? Yes it can, with the Penn Plax Rhino Skull Aquarium Decor. This totally awesome skull will add some edge to any aquarium. It offers fish a place to hide and is crafted of fish-safe, non-toxic resin that's great for saltwater or freshwater settings. About Penn Plax: Penn-Plax is a family-owned company in operation since 1959. They specialize in creating excellent pet supplies for animals both great and small. Best known for producing pet products at affordable prices, the Penn-Plax brand is synonymous with innovation and quality, keeping your pet foremost in mind.