Home » Can Mold Kill Hermit Crabs? [Mildew Tank Safety Precautions]
can hermit crabs die from mold?

Can Mold Kill Hermit Crabs? [Mildew Tank Safety Precautions]

(Last Updated On: September 29, 2022)

Mold, sometimes known as mildew, is a fungal growth that forms and spreads in damp terrain. Mold can be found inside and outdoors of the home, but inside, it relies on moisture to grow. Unfortunately, hermit crab tanks can be the perfect breeding ground for mold.

Hermit crabs need humidity levels of around 80% to breathe safely. With this much humidity in the air, mold can take hold and flourish in a habitat. Mold feeds on dead or decaying organic matter, including spoiled food and rotting wooden decorations.

If you spot mold in a hermit crab enclosure, especially the highly toxic “black mold” (Stachybotrys chartarum), your hermit crabs must be relocated, and the habitat scoured. Not all molds are toxic, but it’s not worth taking any chances.

Suppose your hermit crabs are exposed to mold. In that case, they risk developing fungal infections that scar the gills, the infection aspergillosis that restricts breathing, or so-called Shell Disease Syndrome, which sees the exoskeleton rot away.

Regular cleaning of a hermit crab habitat, such as removing uneaten food and waste, will keep mold at bay. Remain vigilant of any sign of such growth, and take action as soon as it’s noticed.

Why Is There Mold Growing in My Hermit Crab Tank?

Mold is a fungus that thrives in damp conditions. Hermit crabs need a humid habitat to thrive, making a tank the perfect location for mold to take hold and spread.

If you have mold in your hermit crab habitat, the three likeliest causes are:

  • Hermit crabs burying uneaten food in the substrate.
  • One or more wooden decorations are rotting.
  • Humidity levels are too high, exceeding 85%.

Mold comes in many colors, with black mold being the most dangerous.

Mold can also be white, but before assuming that any white substance that clings to walls in a habitat is mold, check it’s not salt crystal residue from a saline cleaning solution.

Can Hermit Crabs Eat Mold?

Hermit crabs are instinctive and curious animals, so they’re likely to investigate if they see any mold. As natural scavengers, many hermit crabs will also attempt to eat mold.

You may believe that hermit crabs can safely eat mold as aquatic hermit crabs consume algae and moss. The fundamental difference is that neither algae nor moss is toxic, just unsightly.

If a hermit crab is fortunate, it’ll consume a comparatively benign form of mold and suffer no ill effects. It’s unlikely that your hermit crabs can distinguish between safe and toxic molds.

The Biological Bulletin explains that hermit crabs avoid consuming foods that previously led to a painful or unpleasant experience. Unfortunately, mold is unlikely to provide a second chance.

why is there mold growing in my hermit crab tank?

Will Mold Hurt Hermit Crabs?

Remove your hermit crabs and clean the tank if you see mold inside the tank. While some molds are non-toxic, you’re unlikely to tell the difference on sight.

Mold isn’t a natural part of a hermit crab’s environment experience, and the longer you leave them exposed to it, the likelier they are to grow unwell.

There are many risks associated with mold for hermit crabs. Various fungal or mycotic diseases can arise when hermit crabs are exposed to mold, damaging the gills. Medical Mycology explains that most of these concerns are zoonotic and contagious.

The common aspergillus mold in a habitat can also lead to aspergillosis, which makes breathing difficult. The presence of aspergillus mold in a hermit crab habitat is also hazardous to any owner with compromised immunity.

The most concerning consequence of mold is shell disease syndrome. Aquaculture explains this condition manifests as black spots on a hermit crab’s exoskeleton. So, the issue is called “black gill syndrome.”

This isn’t just aesthetic imperfection; shell disease syndrome means a hermit crab’s exoskeleton is rotting away. Mold introduces chitinolytic bacteria to a hermit crab, and these bacteria steadily attack and erode the chitins that provide a hermit crab’s exoskeleton.

Can Hermit Crabs Die from Mold?

If your hermit crabs are exposed to mold and develop any of the illnesses discussed, their lives are in danger. Many mold-centric viruses kill hermit crabs, and if just one hermit crab grows ill due to mold, every hermit crab in a tank is at risk.

Shell disease syndrome is the biggest killer. Unless the degradation of a hermit crab’s exoskeleton is halted, it’ll eventually die. Molting seems like a simple solution, but the concern can last beyond a solitary molt and carry over to the replacement exoskeleton.

You also need to consider that other hermit crabs will make the same actions as the hermit crab that grew unwell. This could be breathing in mold, leading to damage to the gills, skin, or exoskeleton, or eating it.

Even if other hermit crabs don’t follow the same actions as their sick tankmate, there’s still a considerable risk to their safety. Clearly, the mold growing in the habitat is toxic.

Consider the behavior of hermit crabs around dead conspecifics, too. If a hermit crab dies due to contact with mold, its shell will quickly be seized – a shell that may contain mold. Equally, the corpse may be eaten by other hermit crabs, who will then consume mold by osmosis.

How to Remove Mold from a Hermit Crab Tank

If you spot mold growing in a hermit crab enclosure, there is no time to waste.

Move your hermit crabs to a different tank devoid of mold. They’ll be here for a while, so ensure humidity and temperature levels are appropriate.

Follow these steps to prevent mold growth from becoming a considerable concern:

  1. Clear the tank. That involves removing all substrate, ornaments, spare shells, etc.
  2. Create a cleaning solution with 3% bleach. You could get a mold-killing habitat cleaner from an exotic pet store, but The Journal of Crustacean Biology confirms that household bleach is effective.
  3. Scrub every inch of the tank with this solution until there’s no trace of mold left.
  4. Create a saline solution and apply it to all ornaments you wish to return to the habitat, then bake them at a low temperature in the oven for 10 minutes.
  5. Rinse the tank and ornaments you cleaned.
  6. Allow the tank and any ornaments to dry in the sun.
  7. Refill the bottom of the tank with substrate, replace any decorations, and return your hermit crabs.

Don’t cut corners throughout this process. All traces of mold must be removed from a tank before your hermit crabs return to their home.

How To Prevent Mold in A Hermit Crab Tank

As crucial as removing mold from a hermit crab enclosure is, preventing it from taking hold in the first place is preferable. Once mold has been established, it is impossible to truly eradicate, and it’ll always return and need to be cleaned.

Regular cleaning is the first step to preventing mold in a hermit crab enclosure. Conduct daily spot cleaning, clearing out fecal waste, uneaten food, or visibly rotten wood. Conduct a full deep clean every month, monitoring conditions in between.

Using saline water when misting your hermit crab enclosure can also keep mold at bay, as salt inhibits fungal growth. Use the saline mix you provide as bathwater for this process, not table salt and tap water, as these are just as toxic as mold to hermit crabs.

If you introduce new ornaments to a hermit crab enclosure, clean them beforehand. Soak the items in salt water for 10 minutes until wholly saturated, then dry them in the sun. This prevents mold from gathering and spreading around your hermit crab’s home.

Mold is a serious concern in hermit crab tanks. Avoid allowing a cleaning regime to grow lax, and vigilantly check for any sign of mold while observing your hermit crabs.