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are hermit crabs harmful to humans?

Can Hermit Crabs Make You Sick?

Hermit crabs have a unique biology. Because of this, owners may get confused about the risk factors involved in keeping hermit crabs as pets. That’s especially true because almost all hermit crabs are wild-caught. Coming straight from the wild, scavenging on decaying matter, and living in a moist environment. That makes it sound like hermit crabs are at high risk of carrying diseases.

Hermit crabs do not carry any diseases that are transmittable to humans. In fact, they don’t carry any disease at all, except for mites and shell disease. These only crop up if the hermit crab is badly cared for, and it cannot make a human sick. Unlike lizards and turtles, hermit crabs are unable to contract or carry diseases like salmonella. They’re even hypoallergenic.

Hermit crabs can make each other sick. That makes it important to quarantine new toys, hermit crabs, and decorations before introducing them to the tank. Likewise, if rotting food, waste, or dirty water is allowed to sit, this will form bacteria and fungus. That can make you ill if you’re exposed for too long.

Do Hermit Crabs Carry Diseases?

Hermit crabs are surprisingly clean and resilient creatures and rarely become ill themselves. Instead, they are 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.

That’s because 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 will be a simple process.

Can Hermit Crabs Get Sick?

Of course, that doesn’t mean hermits are completely immune to illness. Although one cannot get you sick, it can become sick itself.

Exposure to bacteria, foreign agents, and stress can wear down on a hermie’s natural immune system. Like any other creature, when this happens, it’s vulnerable to infections and harmful bacteria.

This can lead to trouble molting, sluggish behavior, and even death, depending on what the hermit caught. That makes it highly important to offer your hermits:

  • A clean environment where waste and rotting food isn’t allowed to get out of control.
  • A well-balanced diet to strengthen their immune system.
  • A calm routine where they aren’t stressed or scared regularly

However, it’s usually stress that makes a hermit appear sick. These creatures lead very simple lives and don’t take well to handling in their natural environments. Getting picked up usually means getting eaten by a bird. Likewise, getting disturbed during a molt often means getting killed by another hermit or a predator.

As such, hermit crabs that are overstimulated can develop the tell-tale signs of illness, even if they haven’t contracted anything official. If the hermit crab does get ill, it still 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 some form of pathogen or bacteria. 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?

It’s true that hermit crabs are capable of making each other sick. That’s especially true if a hermit fresh from the wild encounters a pet hermit that’s adjusted to life in a well-monitored tank. However, the key is that hermit crabs are unable to carry any human diseases.

Even bacteria that can infect a tank of hermits will have no impact on their human owner.  This means hermies are perfectly safe to keep as pets. They can’t make you sick, so you can carry or handle them without worry.

However, it’s still smart to wash your hands before and after touching hermit crabs. This will keep you from getting your hermit sick and limit your exposure to anything the hermit might have smeared on it from the tank.

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 a person developing any illness from it is almost non-existent.

With that said, your hermit crabs may develop their own non-transferable illnesses. This happens when they’re exposed to poor sanitation and housing conditions.


Too much dust in their habitat might attract ectosymbiotic mites. These little creatures can wreak havoc and leave your hermit crab in distress. According to the Journal of Experimental Marine Biology and Ecology, mites can cause the death of their host through excess stress.

Shell Disease

Shell disease is another common health issue that affects hermit crabs. This often comes about from a bacterial or viral infection. Symptoms of shell disease in hermit crabs include colored spots or pockmarks on the hermit crab’s claws, legs, and abdomen. Fortunately, shell disease is not deadly, and your pet can cure itself by molting.

Do Hermit Crabs Carry Salmonella?

Hermit crabs do not carry salmonella, nor can they be affected by it. Salmonella is a type of bacteria present in contaminated food or water. In humans, it can result in symptoms much like food poisoning, such as:

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

Unlike some types of lizards or turtles, hermit crabs are unable to carry or transmit the disease. 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. Hermit crabs are not true crabs. That makes them doubly safe and perfectly healthy to keep in your home.

Do Hermit Crabs Have Venom?

Hermit crabs are unable to make you sick from disease or venom. On the whole, 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.

|hermit crabs are distant relatives to this species. There are over 600 types of hermit crab, and all of them are non-venomous. According to Current Biology, there are two main species kept as pets, namely the Caribbean and Ecuadorian hermit crabs. Both of these only have one real threat against humans: those little grabby claws, which owners already know to stay away from.

Even if your hermit crab does pinch you and break the skin, you are 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. However, it’s unlikely to result in any long-term or short-term illness, even in children or older adults.

what kind of diseases do hermit crabs carry?

Are Hermit Crabs Harmful To Humans?

Hermit crabs are not harmful to humans. They do not carry any human diseases, nor are they venomous. With that said, a hermit crab’s enclosure does have the potential to make you sick. That is if you don’t take precautions. Hermits stay in moist environments that could harbor a wide range of bacteria and fungi.

The best way to limit this is by routinely cleaning and monitoring the tank. After all, it won’t be the hermit making you sick. It will be any bacterial or fungal growths that get out of control. This is often caused by:

  • Introducing unwashed toys or structures to the tank, such as driftwood
  • Providing your hermit crabs with shells that haven’t been properly sanitized
  • Bringing hermits in from the wild and not having a quarantine period
  • Failing to clean away leftover food or general waste
  • Leaving a hermit that’s passed away in the tank for too long

All of these factors will introduce new kinds of bacteria, fungus, and other microorganisms. In the warm, bright environment of a hermit crab tank, they can grow and thrive. At that point, it’s the mold that’s harmful or a disease you’ve brought in on a decoration. The hermit crab is not a carrier and is merely interacting with the contagions you’ve provided.

This will affect the health of your hermit crabs long before it affects you. These small crustaceans will have less resilient immune systems than people. They will also have nowhere to retreat to, while you can simply keep away from the tank. The point where you might get sick will be after:

  • Holding the hermit crab
  • Rearranging its toys
  • Cleaning the tank

That’s why it’s recommended to wash your hands and avoid touching your face while handling these pets. They might not carry diseases, but you can’t be sure if a little fungus or bacteria is hidden on their shell. This is especially true if the tank hasn’t been properly maintained.

Are Hermit Crabs Hypoallergenic?

Hermit crabs are among a special group of animals known as hypoallergenic pets. This means they are safe for people with allergies. Their biology does not contain anything that might trigger an allergic reaction, whether airborne or through touch.

That makes hermit crabs excellent, low-maintenance pets. Their shed skin, even during a molting period, will not trigger a reaction. They do not have hair, nor do they emit a smell that can be irritating to humans. As long as the tank is clean and well cared for, hermit crabs will not affect people with allergies.