Hermit Crabs

Fall is here and it is back to school time. One of the fun things about going to school is the class pet. Students are enjoying learning about the care and responsibility of all sorts of pets in the classroom. One pet who is becoming a big hit is the land hermit crab. These little crabs are very entertaining for kids and adults alike and are relatively easy to care for with a few instructions.
Hermit crabs need a home, which can be simply an inexpensive ten-gallon aquarium. The aquarium must have a substrate covering the floor. This can be clean sand or coconut fiber or better yet something called Calci-sand which has calcium carbonate to strengthen the exoskeleton. The substrate needs to be deep enough to cover the crab because they enjoy digging and burrowing.  The hermit crab needs a shallow water dish;  if the water is too deep the crab will drown.  It needs to be wide enough to fit the whole crab, as he will drag his whole shell into the dish.  Hermit crabs enjoy their toys.  Put toys for climbing inside the aquarium.  Another item for the aquarium is a large sponge.  The sponge adds humidity to the air and keeps the crabs gills moist.  (Hermit crabs use gills to breath, not lungs like humans do.)

Hermit crabs can be fed a commercial hermit crab food.  If it is in pellet form it must be crushed for them to be able to pick it up.  Crabs also like a large variety of foods for treats such as fruits, vegetables, nuts, raisins, applesauce and peanut butter.  Do not feed hermit crabs dairy products because their systems cannot tolerate dairy at all. 

Hermit crabs need water to drink.  It is important to give crabs non-chlorinated water and keep food and water dishes very clean and remove any uneaten portions daily.  One thing to remember about hermit crabs is that they will molt or shed their exoskeleton as they grow.  They outgrow one skeleton and have to grow a new one.  The crab will need you to provide a new shell about one -third bigger than the old one.  Molting takes about two weeks and during this time you must make an effort to keep the crab extra moist by misting with a squirt bottle and feeding a diet higher in calcium to help make a new skeleton. 

One final note to remember is that hermit crabs do pinch.  When they first come home they may pinch a lot because they are hungry and mishandled.  Children may need to handle them with gloves at first.  Kids should handle the crabs over a soft surface like a bed so that if the child drops the crab, it won't be injured.  Generally it is recommended to pick up the hermit crab by the shell, but use caution because they can still reach around to pinch.  Once the hermit crab is acccustomed to being hand fed and handled the incidence of being pinched does become less and less.  They are interesting to watch and a great way to teach kids about crustaceans.

Elizabeth Bixby, DVM