"I personally haven't used this product, but I am a member of a hermit crab care site and they have said it is the WORST possible for hermit crabs. Hermit Crabs need a humid, moist enviroment. If the sand gets wet, it hardens, and can trap your crabs in their shell. It also doesn't do good with molting crabs (monthly shedding of exoskeleton) at all. It also has been known to STINK some times."