Substrate with 0.8 mm grain size for freshwater and marine aquariums and terrariums. Prevents injuries of the mucous membrane: coarse-grained, round-shaped natural sand is gentle on sensitive barbels. Ideal for digging fish, such as rays, kuhli loarch, catfish, etc. Ideal for fish, invertebrates and plants: no unwanted pollutants released into the water. Use: Spread substrate on top of the nutrient substrate (approx. 6 - 8 cm for plants). Well suited for undergravel heating cables. Package contents: 1 bag Sansibar River.