Fish tank substrate can lay the foundation for a striking aquascape. Substrate refers to the material laid on the bottom of the fish tank. Often this is gravel, sand, pebbles or rocks that look similar to the natural environment of fish. Some pets enjoy burrowing, hiding, foraging for food or laying eggs in substrate. And that’s good news! Calm, relaxed fish tend to suffer fewer health problems. Substrate has a key role in biological filtration. Fish tank gravel provides an ideal surface for beneficial bacteria to thrive and help eliminate plant debris, food and fish waste. Browse Aqua One Australian-made fish tank gravel in natural blends and decorative eye-catching tones. Or see the range of Aqua Natural sparkle sand, mini lava rocks, or triple-washed and kiln-dried New Zealand river gravel with metallic highlights. Choose from products that are eco-friendly, non-toxic and have minimal impact on water chemistry.