Originally written by Vanessa Pike-Russell
It is important that your land hermit crabs are able to bathe themselves. Bathing allows your hermit crab to re-hydrate their gills, replenish shell water and adjust the water salinity as well as flush out feces and wash off the sticky juices and food stuffs which are present when you offer fresh fruit, seafood and raw foods.
Hermit Crabs urinate through their antennae, so any water spills during handling is shell water. Hermit Crabs have an anus located on the end of their abdomen, and have been observed to flick any wastes (droppings) out of their shells. These feces are often brown colored and look like small sausage or ball shapes which consist mainly of sand and undigested foodstuffs.
You should provide deep fresh and ocean water ponds that your hermit crabs can wade through and bathe themselves in a “hands off’ method. Both the fresh and ocean water should be treated with dechlorinator, one that removes ammonia. Chlorine will burn a hermit crab’s gills and kill them.
The water dish must be one that they can easily get in and out of, and perhaps has items such as marbles, sea glass, pebbles, piece of coral or other item that will aid in their safe departure from the water, lest they drown.
Bathing after purchase
I do not use the submersion method unless I believe there is a reason, such as decomposing foodstuffs (crabs sometimes hoard food in their shell) or mites. It is stressful for land hermit crabs to be forcibly submerged in water, so it should not be done unless there is a real need. Always use lukewarm de-chlorinated water and be very gentle when placing the crab upside down in the water. Newly purchased crabs can be visibly checked for parasitic mites (attached to gills and joints) kept in isolation for observation and treatment if you don’t want to risk introducing the mites to your main tank.