The key to maintaining healthy happy hermit crabs is to give them plenty of sand. Hermit crabs require deep (3-4x their shell size) and moist sand to properly bury and molt. Zoo med hermit crab sand is made with all natural calcium carbonate and is great for burrowing and hiding. Essential to keeping hermit crabs happy and healthy Provides a natural source of calcium necessary for their health Encourages burrowing, hiding, and other natural behaviors No paints or dyes used Available in: White, Blue, and Green