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are hermit crabs harmful to humans?

Can Hermit Crabs Make You Sick?

(Last Updated On: August 20, 2022)

Hermit crabs have a unique biology, so owners may get confused about the risk factors involved in keeping hermit crabs as pets.

Hermit crabs don’t carry any diseases that are transmittable to humans.

However, hermit crabs can become unwell or make each other sick, so quarantine new toys, hermit crabs, and decorations before introducing them to the tank.

Also, if rotting food, waste, or dirty water is allowed to sit, this will harbor bacteria, mold, and fungus.

Do Hermit Crabs Carry Diseases?

Hermit crabs are surprisingly clean and resilient creatures that rarely become ill. Instead, they’re far more likely to succumb to stress and anxiety when placed in a new environment.

Hermit crabs have a clever way of avoiding long-term illness. They can even prevent themselves from becoming carriers should they have contracted a sickness in the past.

Hermit crabs molt every 18 months or so. In doing this, they shed their original skin and rejuvenate their bodies. They can even regrow limbs during this time, so casting off old infections is a simple process.

Can Hermit Crabs Get Sick?

Of course, that doesn’t mean hermits are completely immune to illness. Although a hermit crab won’t make you sick, it can become sick itself.

Exposure to bacteria and stress can weaken a hermit crab’s immune system. Like any other animal, it’s vulnerable to viruses and bacterial infections when this happens.

This can lead to molting problems, sluggish behavior, and death, depending on what the hermit caught. So, it’s important to provide hermit crabs:

  • An environment free from waste and rotting food.
  • A balanced diet that bolsters the immune system.
  • A calm routine where hermit crabs aren’t stressed or scared.

However, it’s usually stress that makes a hermit sick. These creatures lead simple lives and don’t take well to handling in their natural environments. Getting picked up usually results in getting eaten by a bird.

Overstimulated hermit crabs develop tell-tale signs of illness, even if they haven’t contracted anything. If a hermit crab grows ill, it won’t transmit this to humans.

do hermit crabs carry diseases?

Are Sick Hermit Crabs Dangerous?

Of course, many people think that hermit crabs must carry pathogens.

They live in humid, moist environments, after all. They stay cooped up in their shells and eat decaying matter to fulfill their roles as scavengers.

Since almost all pet hermit crabs are wild-caught, even if you purchase one through a pet store, surely they must bring some diseases from the beach.

Hermit crabs can make each other sick, especially if a hermit fresh from the wild encounters a pet hermit crab in a controlled environment. However, hermit crabs don’t carry human diseases.

Even bacteria that can infect a tank of hermit crabs will not impact a human. However, washing your hands before and after touching hermit crabs is sensible.

What Kind Of Diseases Do Hermit Crabs Carry?

The risk of you contracting a disease from a hermit crab is zero. Waterborne bacteria might be present in your pet’s aquarium, but the risk of developing illness is almost non-existent.

Hermit crabs may develop non-zoonotic (non-transferable) illnesses and diseases, which happen when exposed to poor sanitation and living conditions.


Food can attract ectosymbiotic mites. According to the Journal of Experimental Marine Biology and Ecology, mites can cause the death of their host through stress.

Shell Disease

Shell disease is usually due to a bacterial or viral infection.

Symptoms of shell disease in hermit crabs include colored spots or pockmarks on the claws, legs, and abdomen. Fortunately, shell disease isn’t deadly; a hermit crab can cure itself by molting.

Do Hermit Crabs Carry Salmonella?

Salmonella is a type of bacteria present in contaminated food or water. In humans, it can result in symptoms similar to food poisoning, such as:

  • Vomiting
  • Diarrhea
  • Abdominal pain
  • Fever
  • Night chills

Unlike reptiles, like lizards or turtles, hermit crabs don’t carry or transmit salmonella.

However, that’s not true for all crustaceans. According to the Institute of Tropical Medicine of São Paulo, several strains of vibrio and salmonella can be found in true crabs.

This will only become a danger to people if the crabs are consumed as a meal, not kept as pets. Also, hermit crabs aren’t true crabs.

Do Hermit Crabs Have Venom?

No crustacean is venomous, except for one rare species. This is the Speleonectes tulumensis, which is small and not kept as a pet.

Instead, it hides in the underwater caves of the Caribbean Sea. Using a venom, much like rattlesnakes, can liquefy the organs of other crustaceans.

There are over 600 types of hermit crab, and all of them are non-venomous.

According to Current Biology, two main species are kept as pets, namely the Caribbean and Ecuadorian hermit crabs. The only threat to humans is their claws.

Even if a hermit crab pinched you and broke the skin, you’re unlikely to get sick. You should still clean the wound and disinfect it, as bacteria from the hermit’s cage, water, and sand may cause a mild infection.

what kind of diseases do hermit crabs carry?

Are Hermit Crabs Harmful To Humans?

Hermit crabs don’t carry any human diseases, nor are they venomous.

That said, a hermit crab’s enclosure can make you sick if you don’t take precautions. Hermits live in moist environments that could harbor bacteria and fungi.

The best way to limit this is through routinely cleaning. After all, it won’t be the hermit making you sick; it’ll be any bacterial or fungal growths. This is often caused by:

  • Introducing unwashed toys or structures to the tank, such as driftwood.
  • Giving hermit crabs shells that haven’t been properly sanitized.
  • Bringing hermit crabs in from the wild without a quarantine period.
  • Failing to clean away leftover food or waste.
  • Leaving a dead hermit crab in the tank for too long.

These factors will introduce new bacteria, fungi, and microorganisms. They’ll grow and thrive in the warm, bright environment of a hermit crab tank.

At that point, it’s the harmful mold or disease you’ve introduced via a decoration. The hermit crab isn’t a carrier; it’s just interacting with the contagions you’ve introduced.

Are Hermit Crabs Hypoallergenic?

Hermit crabs are among a group of animals known as hypoallergenic pets, which means they’re safe for people with allergies. Their biology doesn’t contain anything that might trigger an allergic reaction, whether airborne or via touch.

The hair on their legs (males) and shed skin during a molting period won’t trigger an allergic reaction. As long as the tank is clean and well cared for, hermit crabs won’t affect people with allergies.