Fine all-natural sand for land Hermit Crabs, supports digging and burrowing. Best Practices for Hermit Crab Substrate The Mix: Combine sand and coconut fiber (like Eco Tech Coco Peat) at roughly a 5:1 ratio. Consistency: The texture should feel like damp sandcastle sand—holding its shape when poked so tunnels do not collapse. Depth: Layer the substrate at least 15 cm (6 inches) deep, or deep enough for your largest crab to completely bury itself during molting