Hermit crabs defecate through their anus, which is found at the very end of their tail. Being that is where their anus is, their poop subsequently stays in their shell as they go about living their crabby life.

How often do hermit crabs poop?

Hermit crabs use their short rearmost legs to flick waste out of their shell every day or two. This will land on the substrate.

Do you have to clean a hermit crab's cage?

Whether your hermit crabs live in water or a dry tank, their aquarium must be cleaned regularly. Hermit crabs like to remain hygienic, growing distressed in unsanitary conditions. What's more, a dirty habitat can be hazardous to the health of hermit crabs. A hermit crab tank should be spot cleaned every 2-3 days.