Why Did My Hermit Crab Die? 6 Common Reasons

Realizing your pet is dead is always the beginning of a sad story. Especially if you have kids around or if you have been sharing your home with such a pet for a long time now.

And not knowing what caused the death of your dearest pet is simply rubbing salt in the wound. If you are asking yourself “why did my hermit crab die?” we hope this writing will help you find the right answer. And, consequentially, to avoid that happening in the future.

Wrong Tank Setup

In the wild, hermit crabs can sometimes walk for miles and miles before deciding to take a rest. So, can you imagine how sad can they get into a cramped tank in captivity?

Choosing the appropriate tank size is therefore essential. Although they can survive in smaller tanks, we find a 20-gallon aquarium as the ideal starting home.

Another important factor is ensuring your hermit enclosure allows proper ventilation, as temperature and humidity will get high.

Next, it is important to provide a great amount of substrate and to simultaneously choose the appropriate type. This may seem as a not important factor to some people but having enough place to hide is vitally important to these little creatures.

Also, it is better to avoid sand substrate as this can harden inside their shell and joints, but rather to choose soft coconut fiber.

Water Poisoning

Water is essential to all living beings, but hermit crabs especially rely on hydration to thrive. They require both fresh and saltwater, but these need to be de-chlorinated.

Tap water contains minerals that are deadly for these pets and needs to be avoided at all times. Also, choosing the right de-chlorinator is just as important as following the amount guidelines from the manufacturers.

Next, it is necessary to choose the right salt solution for preparing the perfect saltwater. Avoid kitchen salt at all times but choose aquarium salt which is used to re-create the right mineral value of ocean water.

And finally, make sure to change their water frequently and to wash their dishes when doing that. De-chlorinated water does not have to be changed daily, but every 2 or 3 days is more than enough.

If any of these water requirements go out of range, there is an almost inevitable possibility of your hermit dying due to water poisoning.

Low Humidity

Low humidity is, sadly, one of the top death causes among pet hermit crabs. Indeed, when the right levels are not provided, these creatures will suffocate to death. Perhaps not in a week or two, but they will eventually.

Hermit crabs breathe through modified gills, unable to breathe in water and unable to collect dry air, so they need moist to help them absorbing oxygen.

This is extremely important and you should never rely on your personal estimate, but to constantly monitor the hygrometer values instead.


Temperature is just as important as humidity and it needs to be stable at all times. Hermit crabs require tropical temperature values in order to survive.

When these are too low, they will not be able to properly moving or even feeding and will consequentially die. On the other side, if their environment is too hot, they can literally die from overheating.

Again, the safest and most accurate way of knowing the values and being able to react on time is by placing a high-quality thermometer at the middle of the tank.

Molting Problem

While molting, hermit crabs are extremely vulnerable and basically, any contact with external factors can potentially kill them. Moving your crab when it is already buried or letting other crabs disturb it can almost certainly cause their death.

But not only, as even a not thick enough substrate can force them to move and die. Exactly, if they have to move during molting, they can easily die. Once they lose their old exoskeleton, their bodies can literally fall apart if disturbed in any way.

Other connected issues can include a lack of darkness, which can consequentially make them not release enough molting hormones. Or even a poor choice of food that cannot build enough nutritive supplies until the molting is complete.

Finally, as older and bigger your pet gets, the more time and effort will it need to molt, making each such process extremely sensitive.

Disease or Parasite

Although hermit crabs are quite healthy pets, they are vulnerable and can get easily affected by an illness or by parasites if their maintenance is poor. And if such a state is not spotted and treated on time, it may ultimately kill them.

These can include mites or bacterial infections, as well as respiratory diseases or the loss of limbs caused by highly stressful situations.

Is Your Hermit Crab Dead?

If you are suspecting that your hermit crab is dead, this is really easy to confirm. Firstly, a dead crab will start emitting a fishy odor in just a few hours, so smell is often the safest indicator.

If it has been dead for several days already, the entire enclosure will feature a really bad and strong smell. A visible sign of death is the skin coloration, which will be greyish.

Also, their bodies will be rigid but loose in the shell, so if you pick it up it may fall out. Some crabs lose their limbs after dying.

Wrapping Up

It is hard to detect the cause of death in a hermit crab, but you can easily cross out the possible reasons by following our parameters described above.

Providing them the ideal environment as well as taking great care of what they eat and drink is the best way to ensure a happy life for your hermit pets. Do regular cleaning and maintenance along with constant monitoring of their behavior is just what it takes to ensure them a long life.

And remember, hermit crabs are sociable animals and should always be housed into mini-colonies of 3 or more. Depression is just as a possible death cause as all others.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

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