why would a hermit crab die?

Why Did My Hermit Crab Die?

Last Updated on: 16th August 2023, 11:19 pm

There are examples of hermit crabs living for upward of 40 years in the wild. Sadly, many hermit crabs fail to survive in captivity for more than a few weeks.

This implies that the physical needs of hermit crabs aren’t properly met. Inevitably, new owners learn about the care needs of hermit crabs as they go along, which can lead to life-ending mistakes.

It can sometimes be hard to tell if a hermit crab is dying. For example, molting behaviors can resemble death. You must be certain that your hermit crab is dying before taking action.

Why Would a Hermit Crab Die?

Owners can enjoy the company of their pet hermit crabs for decades, but that requires expert care because they’re easy to inadvertently harm.

Hermit crabs are considered low-maintenance pets for children but are delicate and vulnerable to our unintended actions. Unfortunately, most hermit crabs die in captivity after just 1-2 weeks.

Inappropriate Environment

It’s difficult to replicate a hermit crab’s natural habitat because they’re used to living free on the beach, not in a tank. Beachfront shops may sell painted hermit crabs as souvenirs, but they’re living creatures.

To help hermit crabs flourish, they require the following items in their living environment:

  • Space – At least a 10-gallon tank.
  • Warmth – The temperature should be 80 degrees Fahrenheit.
  • Humidity – The tank must be solid and run to 80% humidity.
  • Substrate – Provide a sand substrate for burrowing during molting.
  • Water – A small bowl of salt water to submerge in and regular water (not tap water) to drink.
  • Hiding places – Barriers and obstacles to hide.
  • Company – Hermit crabs are social and don’t enjoy living alone.

You’ll also need to provide the right types of food and hermit crab-safe hydration.

Stress and Loneliness

Hermit crabs like to live in large groups of up to 100. So, a hermit crab forced into captivity alone will be bored and lonely, leading to stress.

As with all animals, chronic stress will shorten a hermit crab’s lifespan. Other causes of stress include:

  • Inability to hide
  • Inappropriate temperatures and humidity
  • Poor diet or water
  • Lack of space
  • Unsanitary living conditions
  • Excessive handling

A stressed hermit crab usually isolates itself or sheds limbs as a defense mechanism.

Will a hermit crab die if it loses a leg? Not necessarily, as hermit crabs regenerate lost limbs over time. However, it’s unlikely to recover if a hermit crab loses multiple limbs.

what happens when a hermit crab dies?

Insufficient Substrate

If a hermit crab died while molting, it was likely due to insufficient substrate. Hermit crabs are vulnerable while molting, so they bury themselves under sand until the process is completed.

Provide around 6 inches of substrate for hermit crabs. Play sand that you would use in a child’s sandpit is ideal, but never use a calcium stand because this will harden hermit crabs’ joints.

Add moisture to the substrate, as hermit crabs need 80% humidity. Ensure the temperature is 80 degrees because this is the optimum temperature for molting hermit crabs.

Never dig up a molting hermit crab from its sandy hiding place because this will cause significant stress. Wait for a hermit crab to surface from the substrate, which could take 8 weeks.


80% humidity is important to a hermit crab, or it’ll suffocate slowly. This is why hermit crabs require solid aquariums and not wire cages.

Get a humidity gauge to determine the humidity level. Then, use a misting spray (when necessary) to reach this optimum level. Without this, hermit crabs’ lungs dry out.

This will involve several weeks of intense discomfort for the hermit crab. In addition, its breathing will suffer before death, with the hermit crab growing increasingly weak before succumbing.

You should leave hermit crabs in their tank as much as possible. Removing them for occasional handling or cleaning is OK, but house them somewhere equally humid.


Land hermit crabs have gills and occasionally need to submerge themselves in water but can’t breathe underwater indefinitely. As per Arthropod Structure and Development, the lungs of land hermit crabs have evolved for terrestrial living.

How long hermit crabs can breathe underwater is uncertain, but it’s around 30 minutes. The hermit crab will instinctively know when it needs to leave the water.

So, ensure hermit crabs have a clear path back to dry land. If necessary, provide vines and branches to climb. If hermit crabs appear distressed in water, they need a shallower pool.

However, you shouldn’t provide a shallow bath because hermit crabs need to submerge occasionally, which cleans the shell and fills it with essential water.

Toxicity and Poisoning

Hermit crabs purchased from seafront gift shops are particularly vulnerable to this demise. A lack of understanding of dietary and hydration requirements also leads to death.


Hermit crabs need salt water for bathing and freshwater for hydration and carrying in the shell.

Hermit crabs must never be given tap water because it contains chlorine and heavy metals, which are toxic to hermit crabs. Tap water can cause seemingly inexplicable death.

Bottled or filtered water is recommended for hydration.


While hermit crabs are natural scavengers, they have dietary preferences.

You could get pellets from a pet store, but it’s not recommended because they can contain insecticides and toxic preservatives. Also, many hermit crabs will reject pellets because they’re bland.

Offer hermit crabs a varied diet of fruits, vegetables, nuts, fish, and meat because they’ll provide sufficient calcium, protein, and tannins.  

Paints and Dyes

Many hermit crabs are placed in brightly painted shells to make them more appealing for sale. Unfortunately, this aesthetic splendor may cost a hermit crab its life.

Paints are frequently toxic to hermit crabs because the paint chips may be eaten. The term “non-toxic paint” refers to humans, not crustaceans. Also, hermit crabs get stuck inside painted shells.

You’ll also need to be mindful of store-bought aquarium decorations because the humidity of an aquarium may make paint or dye run. Also, colored sand poses the same risk, leading to toxicity.

Only use plain and non-decorative obstacles and beautifications.

Household Chemicals

Avoid using household chemicals around hermit crabs. This means cleaning products used to sterilize the aquarium, such as bleaches and strong chemicals.

Breathing in aerosol fumes can be deadly. So, don’t spray air freshener or antiperspirant around hermit crabs. Even perfume or cologne can have life-threatening consequences.

Inappropriate Shells

Hermit crabs are always looking for new and better shells. Only place natural shells in an aquarium because this reduces the risk of consuming toxic chemicals.

In addition, think carefully about any decorations or obstacles in the tank, as hermit crabs may use anything as a shell. Wild hermit crabs often die when they become trapped in plastic bottles.

Bacterial or Fungal Infections

The aquarium must be cleaned regularly because humidity produces bacteria and fungal growth. These pathogens can be breathed in or ingested by hermit crabs, which can be fatal.

Captive hermit crabs can’t escape undesirable surroundings. Waste, rotting food, and discarded exoskeletons can lead to unsanitary conditions, resulting in stress and illness.

Spot cleaning should be conducted daily, and perform a thorough clean at least once every 2 weeks.

Impact Injuries

Hermit crabs don’t have organic shells, so they’re susceptible to impact injuries.

Rough handling by owners or another pet can kill a hermit crab. In addition, hermit crabs are skilled climbers with poor eyesight, meaning they may stumble and fall from a ledge.

To minimize the risks, provide a grippy surface. Hermit crabs use their pincers to climb, so fill the sides of the aquarium with netting and vines. These will help the hermit crab negotiate smooth surfaces. Also, more substrate will provide a softer landing.

Many ask, “Will a hermit crab die if you drop it?” A fall of three feet or higher can be fatal, as injuries to core body parts may make recovery impossible.

can hermit crabs die from stress?

Conflict with Other Hermit Crabs

While hermit crabs are social animals, they don’t always get along. As per Behavioral Ecology and Sociobiology, it’s not unheard of for hermit crabs to fight to the death.

The most likely cause of inter-crab conflict is resources, as hermit crabs need space from each other. If they’re constantly battling for food, fights will occur. Without enough space, there is no escape.

Hermit crabs can grow insecure over hiding spaces and shells, so ensure both are available to prevent fighting. Also, barriers can provide escape routes and hiding places.

Hermit crabs may battle for dominance, which involves one hermit crab trying to remove another from its shell. This may happen when a hermit crab covets another hermit crab’s shell.

Unsanitary living conditions or stress can make crabs belligerent. If a fight breaks out, separate them, placing the aggressor in a separate area with more shells until it calms down.

Hermit crabs sometimes play-fight for recreation, which involves pushing each other with pincers or feelers. It’ll be clear if hermit crabs are fighting or playing, as neither will attempt to escape.

Misunderstanding The Molting Process

A hermit crab that’s close to death will become solitary and lethargic.

Unfortunately, the same can also be said about molting. So, it’s easy to mistake a molting hermit crab for a deceased one, leading to owners accidentally killing healthy crabs.

Assume that a hermit crab is shedding its exoskeleton. It’ll lay immobile, waiting for its new skeleton to toughen up, providing the strength to move again. Never touch a hermit crab in this state.

Unless you’re certain a hermit crab is dead, don’t separate the body from the shell. You may be tempted to use tweezers to remove the dead crab. Why waste a shell when another hermit crab could use it? Unfortunately, if the hermit crab isn’t dead, you’ve mutilated it.

What Happens When a Hermit Crab Dies?

As discussed, death in hermit crabs is often confused with molting. There are signs that a hermit crab has expired, such as the unmistakable stench.

A dead hermit crab will start to decompose; this odor is putrid and unmistakable. If your room smells like rotten fish, a dead hermit crab is likely, especially if other hermit crabs grow excitable.

Ecology and Evolution explain how this scent of death appeals to other hermit crabs because they’ll investigate the corpse and see if they can scavenge the shell. The dead hermit crab may also be consumed because they’re natural scavengers.

Don’t leave other hermit crabs to take care of the body. If a hermit crab died of toxicity, this could kill other hermit crabs. The dead crab must be manually removed and the tank cleaned.