Hermit crabs are hardy little creatures, but it is possible for them to get sick, especially if they are not cared for properly. Watch your pet hermit crab every day so that you are able to notice the first symptoms of a health problem. Here's how to tell if a pet hermit crab is sick:
- Watch your pet hermit crab's normal behaviors. By making note of your hermit crab's normal behaviors, you'll be better prepared to spot changes in behavior.
- Look for crabs exhibiting unusual behaviors. If any of the pet crabs are running around inside the tank without their shell, or do not retreat into their shells when you pick them up, this is a major sign that a pet hermit crab is sick. Your hermit crab should be in his shell almost always, and hide from you by retreating back into the shell.
- Watch for signs of physical illness on the crab and his shell. Though it is actually normal for crabs to lose a leg or two when adjusting to new environments or other stressful situations, if a crab seems to be losing legs for no apparent reason, your pet hermit crab is probably ill. Look for brown or white specks on the crab. These are mites, and you might be able to see them crawling if you look hard enough. While not technically an illness, mites can nevertheless be bad for your crab's health. Inspect the crabs for other shell discolorations, too, such as fungus or mold. If you find signs of these sicknesses, isolate your crab from the others and give it a bath. Also place a new shell inside the tank in case your crab wants to change to a cleaner one.
- Look for inactivity. If a hermit crab is persistently inactive, this does not necessarily indicate illness. Your crab may simply be telling you that his environment is not suitable. Make sure that your tank is kept at an appropriate temperature and that it is clean. Many hermit crabs that appear sick can be helped simply by adjusting the humidity or temperature.
- Pay attention to odors. If a hermit crab has died, you will notice a strong, fish-like odor. A molting crab, on the other hand, may be relatively inactive, with a slight odor. What he needs is a tank with lots of substrate where he can bury himself, as well as plenty of food and water. While a crab that is molting is not technically sick, he does require specialized care, just like sick hermit crabs. Try not to disturb a crab that is in the middle of the molting process.
If you have several hermit crabs and you think that one of them might be sick, it's important to place the sick hermit crab in an isolation tank so that he doesn't get your other crabs sick. Cleaning the hermit crab's tank frequently can also reduce the occurrence of illnesses.