Creating a thriving vivarium is an incredibly rewarding experience, but even the most carefully planned vivariums can run into a few challenges along the way. From stubborn mould outbreaks to unwanted pests, every vivarium keeper encounters problems at some point or another. The good news is that most common issues have straightforward solutions once you know what to look for.
In this handy guide, we'll explore some of the most frequent vivarium problems, explain why they happen, and share practical tips to help you get your setup back on track. Whether you're building your first bioactive enclosure or maintaining a long-established ecosystem, these expert tips will help keep your vivarium healthy, balanced, and looking its best for your scaly friend.
1. Tank mould (white fuzz)
White fuzzy mould is one of the most common issues reptile keepers face. While small amounts are usually harmless and won’t bother your pets, avoiding the issue could cause it to spread. If you notice lots of white mould, this could be a sign of other issues, like excessive moisture or poor enclosure maintenance.
Common causes:
Vivarium mould often appears when excess moisture combines with decaying organic matter such as leaf litter, wood, moss, or uneaten food. Mould is particularly common in tropical set ups as the warm, humid conditions are ideal for fungal growth, especially during the first few weeks after setup when the enclosure is still finding its biological balance.
Other reasons for mould growth in vivariums include:
- Excessively high humidity with limited airflow
- Uneaten food left in the enclosure
- Decaying plant material or excessive organic waste
- An immature bioactive system without an established clean-up crew
How to fix it:
Luckily, there are a few simple ways you can tackle mould growth to prevent it from becoming a bigger problem.
Improve the air circulation - make sure your vents aren’t blocked or clogged. This will allow for maximum airflow. You can also try moving plants and decor if necessary to promote better air circulation. This will help to reduce stagnant, damp areas from forming and prevent the mould from growing further.
Remove affected material - If mould is found on organic matter, like a piece of wood, leaf litter, or food item, remove it and replace with a fresh version to prevent further spread.
Spot cleaning - Once you’ve removed the mould, target and clean the areas it was found in to stop it from growing back. Use a reptile safe disinfectant such as this Beaphar Deep Clean Disinfectant which helps to prevent fungal, bacteria and viral infections from circulating in your reptile environment. You can use disinfectants to clean any affected walls, surfaces, decorations and even feeding bowls, so long as it’s safe to use your reptile pets! Make sure to check the manufacturer packaging if you’re not sure.
Beaphar Deep Clean Disinfectant Reptile - £10.45
Add a clean-up crew - Springtails are very small, insect-like creatures. They love eating mould, decaying organic matter, and fungi - so they’ll quite happily help tackle your mould problem. In bioactive vivariums, they are often the best long-term solution. They aren’t a complete solution to the problem as they’re microscopic so they will struggle to tackle large amounts of mould but they do act as a preventative barrier against mould growth to prevent future incidents. If you’re interested in creating this type of ecosystem, you can learn more about vivarium clean-up crews with our dedicated, in-depth, blog.
Avoid overwatering - Too much watering or misting can be another cause of mould growth. You can check whether your enclosure is too wet by checking that the substrate is moist rather than waterlogged. If it’s too wet, allow excess moisture to dissipate. You can do this easily by spreading it around on a paper towel or cardboard to dry it out.
2. Mites and pests
No matter how well-balanced your bioactive vivarium is, sometimes unwanted pests such as mites and fruit flies can make their way into the ecosystem. While a few stray insects are usually nothing to worry about, larger infestations can damage plants, disrupt the ecosystem, and won’t be very pleasant to look at. We’ve created a more in-depth blog on dealing with vivarium mites and pests, as it can be a tricky and frustrating issue but for now, here’s a brief overview.
Common causes
Pests are often introduced when you add new plants, substrate, leaf litter, wood, or other natural décor to your vivarium. Once inside a warm, humid vivarium with plenty of food and shelter, certain species will thrive and can reproduce rapidly if left unchecked. They can also appear when there's a lack of natural predators to eat them!
How to get rid of pests in a vivarium
Pest problems need to be dealt with swiftly to maintain a balanced environment. Below are the most common ways pests can be managed, however, we strongly recommend that you identify the pest first. You’ll need to know which pest is infesting your vivarium, as different pests require different control methods, so knowing what you’re dealing with will help you solve the problem more quickly and efficiently.
Remove heavily affected plants - Prune damaged leaves or isolate severely infested plants by removing them from the tank to prevent the problem from spreading further.
Reduce excess moisture - Many pest species thrive in consistently damp conditions. To help stop them doubling their numbers, avoid overwatering or heavy misting.
Remove uneaten food and waste - Keeping the vivarium clean reduces food sources that support pest populations. This means regular spot cleaning and intermittent deep cleans!
Introduce beneficial organisms - Pests control predators such as springtails, and other beneficial invertebrates that make up a clean-up crew can help maintain balance and suppress certain pest species naturally.
Mite treatment - if the mites are directly affecting your reptiles, you’ll need to rely on treatments, such as this Cloverleaf Absolute Repti‐Vet mite treatment, to help eliminate the infestation.
3. Sour-smelling substrate
A healthy vivarium should have a fresh, earthy smell, just like a thriving natural ecosystem. So, if your substrate develops a sour, rotten, or unpleasant odour, it is usually a sign that something is out of balance within your set-up.
Common causes
Sour-smelling substrate is most commonly caused by anaerobic conditions, where excess moisture prevents oxygen from reaching the deeper layers of the substrate. When this happens, harmful bacteria begin breaking down organic matter without oxygen, producing foul-smelling gases and creating unhealthy conditions for plants, clean-up crews, and the enclosure inhabitants.
Other causes include:
- Overwatering
- Waterlogged substrate
- Poor drainage or the absence of a drainage layer (especially in tropical set ups)
- Excess organic waste, such as uneaten food or animal waste
- Dead plant roots decomposing beneath the surface
- Insufficient clean-up crew activity
How to fix sour-smelling substrate
If your substrate is starting to smell, the best thing you can do is replace it with a fresh layer and start again. However, in order to avoid sour-smelling substrate from reoccurring, you should follow these steps:
Check the drainage - Ensure excess water can move away from the substrate. If your vivarium lacks a drainage layer (drainage layers are especially important for tropical and humid set-ups), you may need to redesign the enclosure to prevent water build-up and allow more room for evaporation and airflow.
Reduce watering - Allow the substrate to dry slightly between watering sessions. However, be mindful that you are providing sufficient watering for the plants and animals in the enclosure.
Aerate compacted areas - Gently loosen heavily compacted substrate to improve airflow, making sure that oxygen can get through.
Replace affected substrate if necessary - In severe cases where the smell persists, replacing sections, or all of the substrate may be the most effective solution.
4. Algae growth
Algae is common in tropical or humid setups, a small amount of algae is a natural part of many vivarium ecosystems and is often a sign of a moist, healthy environment. However, when algae begins to spread rapidly across glass, decor, substrate, or plants, it can become unsightly and can indicate an imbalance within the enclosure.
Small amounts of algae growth is particularly common in newly established vivariums, but this shouldn’t worry any beginner vivarium enthusiasts, as this is normal and even beneficial for the vivarium.
Common causes
Excessive algae growth happens when the conditions of the vivarium are just right for it to thrive. While algae is generally harmless, uncontrolled growth can compete with the plants in the vivarium, reduce visibility through the glass, and generally looks quite unpleasant or dirty. Algae overgrowth can also lead to reduced oxygen for your pets, and in certain species like turtles, it will start to grow on them.
Common Causes include:
- Excessive light exposure
- High humidity
- Poor airflow within the enclosure
- Excess organic waste breaking down in the system
How to fix excessive algae growth
When the algae spreads around the vivarium and becomes unsightly, this is usually a sign that it’s getting out of control, and it’s time to tackle the issue. Below you can find some great ways to tackle algae overgrowth.
Reduce light exposure - Shortening lighting periods or adjusting light intensity can help prevent an overgrowth of algae; however, you should only do this if your plants and animals will still be getting enough light to suit their needs. If lowering light exposure will harm the inhabitant's well-being, you should avoid this step.
Improve airflow - Increasing ventilation can help reduce the damp conditions that encourage algae growth.
Clean affected surfaces - Gently wipe algae from glass, décor, and hard surfaces before it has a chance to spread further. Consistent cleaning will help prevent future overgrowth.
Check humidity levels - your humidity levels can have a big impact on algae growth, double check your humidity levels are correct for your enclosure and check that nothing is impacting airflow to prevent excessive algae growth.
5. Dying plants
Healthy plants are the foundation of a thriving vivarium, providing natural beauty, improving air quality, and contributing to the overall balance of the ecosystem. However, when multiple plants begin to decline or die, it is often a sign that environmental conditions are not meeting their needs.
Common causes
Excessive plant loss can result from a variety of factors, including improper lighting. Because vivariums are enclosed environments, even small imbalances can have a significant impact on plant health over time.
Common causes include:
- Insufficient or excessive lighting
- Overwatering or underwatering
- Poor drainage leading to root rot
- Nutrient-deficient or unsuitable substrate
- Temperature or humidity levels outside the plant's requirements
- Plant species that are not suited to vivarium conditions
- Damage from pests, disease, or animal inhabitants
How to fix dying plants in a vivarium
In order to avoid dying plants, you should always ensure you’re buying the correct plants for your set-up. For example, desert species for desert environments and tropical plants for humid environments. Other ways you can fix or avoid dying plants in your vivarium include:
Assess lighting conditions - Ensure plants are receiving the correct intensity and duration of light for their species. Consider upgrading your lighting if necessary, or change their placement to ensure they’re not being blocked by other decorative items or plants.
Check moisture levels - The substrate should remain appropriately moist for the plants being kept without becoming waterlogged.
Inspect plant roots - Remove affected plants and check for signs of root rot, such as blackened, soft, or foul-smelling roots.
Match plants to the environment - You should choose species that naturally thrive in the humidity, temperature, and light conditions provided by the vivarium.
Prune dead growth - Removing damaged or dying material allows healthy growth to receive more resources and reduces the risk of decay-related issues.
Having the right lighting - Certain reptile bulbs and lamps can burn plants in your terrarium. LED lighting, such as this Arcadia Jungle Dawn light, is the best choice for plant health as it provides specific wavelengths that drive photosynthesis.
Arcadia Jungle Dawn Full-Spectrum LED Bars - £47.95
Other common vivarium issues to watch out for
To maintain a healthy vivarium, solid foundations and a balanced ecosystem are key to avoiding many of the common problems that beginners and experts alike can experience. Below, we’ve included some other areas you should be aware of when creating a thriving and problem-free ecosystem.
Inadequate lighting
Proper lighting is essential for the health and well-being of reptiles, particularly species that require UVB exposure to regulate calcium metabolism and support normal bodily functions. Inadequate lighting can lead to signs such as lethargy, reduced appetite, poor growth, dull colouration, difficulty shedding, and, in severe cases, metabolic bone disease.
To keep your vivarium healthy, ensure your enclosure has the appropriate UVB bulbs for your reptiles and habitat. Read the manufacturer's instructions to understand where and how to place them. Regularly monitoring your reptile's behaviour and the enclosure's lighting setup will help ensure they receive the light they need to thrive. If you want to learn more, read our full guide to vivarium heating and lighting to understand your pets and their needs better.
Incorrect humidity levels
Maintaining the correct humidity levels is essential for the health of plants, microfauna, and animal inhabitants within a vivarium. When humidity is too low, plants may develop brown leaf tips, wilt, or struggle to grow, while animals can experience shedding difficulties and dehydration. Excessively high humidity can lead to condensation on the glass, mould outbreaks, fungal growth, and an increased risk of root rot.
To fix humidity issues, regularly monitor levels using a reliable hygrometer and adjust misting, ventilation, or drainage as needed. Misting systems such as this HabiStat Digital Timer Humidifier will help ensure consistent levels of misting, taking the guesswork out for reptile owners and creating a healthier habitat.
ZooMed Digital Thermometer/Humidity Gauge - £14.99
HabiStat Digital Timer Humidifier - £63.99
You can also read through our full guide to vivarium misting systems for more advice on maintaining proper humidity levels.
Poor ventilation
When ventilation is inadequate, stale, humid air can become trapped inside the enclosure, creating ideal conditions for mould, fungal growth, algae, and pest outbreaks. Common signs of poor ventilation include excessive condensation on the glass, persistent damp areas, unpleasant odours, and declining plant health.
To avoid improper airflow, make sure ventilation openings are clear and unobstructed to increase the airflow where possible. You should also avoid overcrowding the enclosure with décor or plants that restrict air movement for the best circulation.
Incorrect temperatures
Temperatures that are too high can cause wilting, dehydration, heat stress, and reduced activity in your plants and pets, while temperatures that are too low may lead to slow plant growth, poor metabolism in animals, and declining microfauna populations. Some common signs of incorrect temperatures to keep an eye out for include struggling plants and lethargic animals.
To avoid temperatures getting too hot or dipping too cold, you should regularly monitor conditions using reliable thermometers such as this Exo Terra Thermostat, which comes with precise temperature control. As well as using appropriately sized heating equipment such as this Exo Terra Daytime Heat Lamp to keep the temperature within the healthy range for your habitat and animals. Always ensure you’re reading the product's requirements to understand exactly which items will best suit your scaly friends' needs.
Exo Terra Thermostat 300w Dim/Pulse Prop - £51.99
Exo Terra Daytime Heat Lamp - £8.95
Avoid common terrarium problems with Aquacadabra
Every vivarium faces challenges from time to time, whether it's mould appearing unexpectedly, plants struggling to thrive, or environmental conditions drifting out of balance. The good news is that most common vivarium problems are fixable with a little observation, patience, and routine maintenance. By understanding the causes behind these issues and addressing them early, you can create a healthier, more stable ecosystem for your plants, microfauna, and animals.
Learn more about keeping your vivarium clean, healthy and stable here at Aquacadabra and browse our blogs for more valuable care advice like how to properly set up a vivarium, or get ready to build your first thriving ecosystem and browse our full vivarium range.