HERMIT CRAB CARE

Thomas H. Boyer, DVM

9888-F Carmel Mountain Road

                                          San Diego, California (858) 484-3490

Hermit crabs, Coenobita clypeatus, are tropical land crabs found in close association with beaches in  Florida and the Caribbean. They are popular pets but, as with any animal, they have special requirements which must be met for them to do well in captivity.

Five to ten gallon aquariums (or larger if you prefer), filled with 2 to 3 inches of sand and gravel, make good cages. Dirt or potting soil is difficult to keep clean and should be avoided. A secure lid is important because hermit cabs are agile climbers.  An aquarium hood with a light helps keep humidity up in the cage.  A screen top also works well but be sure to spray the cage with water several times per week to keep up humidity. The cage should be humid but not wet (if water is always beading up on the glass it's too humid).  Hardwood driftwood branches allow the crabs some space for climbing.

Fresh clean dechlorinated water should always be available in a shallow non-metal dish. The water should be just deep enough so that the crab can get its gills wet but not so deep they can become submerged or they may drown.  Make sure the water is cleaned whenever dirty or several times per week.

Cage temperature should be 75 to 85º F.  If your house is not this warm heating pads or heat tape underneath the aquarium or a hot rock buried in the sand and gravel may keep it warm enough.  Get a thermometer so you know  what the temperature is for sure. 

Hermit crabs eat a wide variety of foods in the wild consequently they are good eaters in captivity. One should feed them a wide variety of foods such as commercial hermit crab diets, dry dog food, poultry rations, pelleted fish food, bread, peanut butter, oatmeal, various vegetables and fruits (such as apples or coconut).  Hermit crabs eat very small amounts of food but like to carry off uneaten food and bury it, so be sure to remove uneaten portions so it does not spoil in the cage. Periodically break down the entire cage and rinse it out well with hot water. A clean cage and varied diet are two of the most important things you can do to keep your crab healthy.

Hermit crabs, like other crabs, have a hard outer skeleton (the exoskeleton) which must be shed periodically so that the crab can grow and regenerate missing limbs. Younger crabs molt every 12 to 15 months. A few days before shedding the hermit crab will become much less active and stop eating. The old exoskeleton cracks open and the hermit crawls out of it and the shell in which it has been residing. The new exoskeleton is larger but very soft and susceptible to injury, infection and desiccation. Once your crab molts it needs a moist clean retreat to burrow into. Leave it alone (do not handle it at all) until the exoskeleton hardens, which takes roughly 10 days. The crab will soon seek a new larger shell. Give your crab a few shells to choose from but make sure they have oval to round openings (rather than slit like openings), counterclockwise spirals and have been thoroughly cleaned out. Your crab may try on several shells several times before it decides which shell is best. Leave the shed exoskeleton in the cage as a mineral source for your crab.