Gravel Black, i.e. black gravel, is a natural substrate for the aquarium. It has slightly reduced edges and gently shines. It can be used in any aquarium due to the fact that it does not change the water parameters. It creates a beautiful scenery in the reservoir, emphasizes the colors of fish and plants. Clean, non-toxic, 100% safe, packed in original packaging. It can be wet in the package, or you can pre-rinse it before use.