For larger aquariums looking for some historical significance, there"s the Penn Plax London Bridge Aquarium Decor - Right Side. Combined with the left side, this decoration makes a large London bridge that both you and your fish will love. It"s crafted of non-toxic resin that"s great for saltwater or freshwater aquariums. * Constructed form durable resin * Designed for both fresh and salt water aquariums * Will not alter the water chemistry * Perfect place for your fish to hide and play * Dimensions: 10.75L x 7.5W x 13H in.