One of the most popular pets of all time, hermit crabs often provoke childhood memories of the tiny crustaceans scuttling about their cages. Fun, interesting, and easy to take care of, hermit crabs are, however, prone to certain conditions that every owner and potential owner should be made aware of.
Common in the pet trade, hermit crabs have been pets for decades. Though often described as a “beginner’s pet” for children, they do have a rather extensive list of requirements and are known to actually live much longer than typically expected. Certain species of hermit crabs can live for upwards of 20 years, provided they’re properly cared for. Being crustaceans, they are prone to afflictions common to that group, including some unique in their regard, many of which involve infection. There are no “diseases” specifically, but a few conditions that adversely affect their health.
Shell rot, or shell disease, is known for attacking not just hermit crabs but other arthropods as well, including lobsters and crayfish. This affliction appears as dark, rust-colored spots on the exoskeleton of your hermit crab, differing greatly in appearance from the normal, freckle-like spots on their forelimbs. This is caused by a fungal infection, with the fungi feeding on the seeping chitin of the crab’s shell. Under normal circumstances, the infection is brought about via injury, like cracks in the shell.
If a hermit crab is injured and severs a limb, the fungus becomes deadly, as it will infect the severed region with ferocity. If this persists, the shell rot will advance to literal holes in the exoskeleton, allowing for the passage of bacteria. Once this happens, your hermit crab will continue to decline in health.
Though not a disease, stress is the primary killer of hermit crabs. In the wild, hermit crabs are known for traveling several miles a day in a constant search of food or larger shells. If they’re placed in a tank that is either overcrowded, of inadequate size, or is in poor condition, the crab may begin to drop limbs and develop shell rot.
Prevention and Care
Cleanliness is the best way to keep your hermit crabs from getting sick. Maintaining a good-sized cage or tank, providing fresh water, clean food, and progressively larger shells should be enough to keep your crab healthy. If, by chance, it does develop shell rot, the only effective measure against it is molting, whereas the old exoskeleton slips right off in favor of a newer, healthier one underneath. Molts can be promoted by a diet high in protein and calcium and an assortment of larger shells.