Fluker's Natural Sea Sponge for Hermit Crabs Water Bowl Access! NEW! No Drowning! Hermit crabs can drown if they are not able to get out of their water bowls. Place a sponge in each water dish to allow crabs a safe way in and out. Sponge may be moistened with purified water to maintain humidity level in a small enclosures. Sponges also contain nutrients such as Chitin and bits of natural shells that crabs will eat and are beneficial for their exoskeleton. Fast Shipping! Enjoy!