Fungi that grow as multicellular strands, called hyphae, are defined as mold. Any natural materials in a hermit crab tank can experience biodegradation due to mold growth.
Hermit crabs need a humidity level of around 80% to breathe. With so much humidity (moisture), mold can flourish. Mold feeds on dead and decaying organic matter, including rotting food and wood.
If you find mold (a type of fungus) in an enclosure, especially the highly toxic black mold (Stachybotrys chartarum), hermit crabs must be relocated while the tank is deep cleaned.
If hermit crabs are exposed to mold, they risk developing fungal infections that scar the gills and diseases that compromise the exoskeleton’s structure (erosion and pitting), like shell disease syndrome.
Not all molds are toxic, but removing all of them is essential because it’s difficult to identify the species.
Why Is There Mold Growing in My Hermit Crab Tank?
Mold thrives in wet and damp conditions. If you have mold in a hermit crab tank, the likely causes are:
- Hermit crabs have buried food in the substrate.
- One or more wooden decorations are decaying.
- Humidity levels are excessively high, exceeding 85%.
Mold can be of various colors, with Cladosporium, Penicillium, Fusarium, Aspergillus, and Stachybotrys (black mold) particularly harmful to animals and humans.
Mold can also be white. Before assuming that any white substance that clings to walls is mold, check it’s not a salt crystal residue from a saline cleaning solution.
Can Hermit Crabs Eat Mold?
Hermit crabs are instinctive and curious animals that will likely investigate mold growth.
While hermit crabs have been observed eating mold on sandy beaches in the wild, scientific experts consider it dangerous in an enclosed environment like a tank.
You may believe that hermit crabs can safely eat mold as aquatic hermit crabs consume algae and moss. The difference is that neither algae nor moss is toxic, just visually unsightly.
A hermit crab may consume a benign mold and suffer no ill effects. However, it’s unlikely that hermit crabs can distinguish between benign and toxic molds.
The Biological Bulletin explains that hermit crabs avoid foods that previously led to painful or unpleasant experiences. Unfortunately, deadly molds won’t give hermit crabs a second chance.
Will Mold Hurt Hermit Crabs?
Remove the hermit crabs and clean the tank if you see mold inside the tank. Always wear a mask.
Various fungal or mycotic diseases can arise when hermit crabs are exposed to mold, damaging the gills. Medical Mycology explains that most concerns are zoonotic (passed on to humans).
The common Aspergillus mold can also lead to Aspergillosis, which makes breathing difficult. The presence of Aspergillus mold is hazardous for those with compromised immunity.
The main consequence of mold is shell disease syndrome. Aquaculture explains that shell disease syndrome manifests as black spots on the exoskeleton, called “black gill syndrome.”
Shell disease syndrome involves a hermit crab’s exoskeleton rotting away. Mold introduces chitinolytic bacteria to a hermit crab’s protective exoskeleton, attacking and eroding the chitin.
Can Hermit Crabs Die from Mold?
If hermit crabs are exposed to mold, especially for a prolonged period, it can be life-threatening.
While some forms of mold are allergenic, others are scientifically classified as toxigenic. Some types of mold are both allergenic and toxigenic, like Aspergillus.
Mycotic and fungal diseases kill hermit crabs by compromising the exoskeleton and scarring the gills.
If a hermit crab dies due to mold exposure, its shell will be taken by a rival – it may contain toxic mold. Other hermit crabs may also eat the corpse, leading to mycotoxicosis.
How to Remove Mold from a Hermit Crab Tank
Move the hermit crabs to a mold-free tank. They’ll be there while the tank is cleaned and given time to dry, so ensure the humidity and temperature levels are set appropriately.
Follow these simple steps to prevent mold growth in hermit crab tanks:
- Clear the tank. This involves removing all substrate, ornaments, spare shells, etc.
- Create a cleaning solution with 3% bleach. You could buy a mold-killing habitat cleaner from an exotic pet store, but The Journal of Crustacean Biology stated that bleach is equally effective.
- Clean the entire tank with this solution until no mold remains.
- Apply a saline solution to all ornaments. Then, bake them in the oven for 10 minutes.
- Rinse the tank and ornaments you cleaned until you can no longer detect the smell of bleach.
- Allow the tank and ornaments to dry in the sun.
- Refill the bottom of the tank with new substrate, replace any decor, and return the hermit crabs.
All traces of mold and toxic substances must be removed from the tank.
How To Prevent Mold in A Hermit Crab Tank
Regular cleaning is the first step toward 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 living conditions daily.
Use saline water to mist the enclosure and keep mold at bay. Salt inhibits fungal growth.
Use the saline mix you provide as bathwater for this process. Don’t use table salt and tap water because these are as toxic as mold to hermit crabs, perhaps more so.
If you introduce new ornaments to a hermit crab enclosure, clean them beforehand. Soak everything in salt water for 10 minutes, allowing them to dry naturally in the sun (if possible).
Mold is a severe problem for hermit crab tanks, as humidity promotes growth. Avoid allowing a cleaning regime to grow lax, and check for signs of mold while observing the activity of hermit crabs.