For larger aquariums looking for some historical significance, there"s the Penn Plax London Bridge Aquarium Decor - Left Side. Combined with the right 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. * Durable resin construction * Designed for both fresh and salt water aquariums * Non-toxic and fish-safe * Perfect place for your fish to hide and play * Dimensions: 10.75L x 7.5W x 13H in.