Light, fine substrate with black pebbles for freshwater and marine aquariums.Key Features:• Substrate with 0.8mm 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. 6-8cm for vigorous plant growth). Well suited for undergravel heater cables.