There is a misconception that placing some plants, some soil, and a clean-up crew in with your reptile or amphibian, and hey presto you have a bioactive vivarium. Bioactive setups involve designing and maintaining sustainable, self-contained terrariums that incorporate beneficial microfauna, plants, and suitable substrates to support a balanced ecosystem. Sadly, creating a truly balanced ecosystem is not that easy and requires careful planning, layering, and ongoing management.
What is a bioactive vivarium?
A simple definition of bioactive is that it has an effect on a living organism. But the term as we use it means that there is an entire living ecosystem in the vivarium, where the pivotal role of microfauna and substrate layering helps maintain balance by allowing waste, including animal waste, to be broken down and the resulting nutrients to be used by other inhabitants of the vivarium, for example, plants, insects, animals, and yes isopods.
In practice, you will need to do some cleaning, and it will take months, if not years for it all to balance out. It’s also advisable to replace substrate periodically, a section at a time, and if you have a drainage layer, make sure it doesn’t go stagnant. But despite all that, it’s worth it. You will be providing your inhabitants with all the extra things that might be missing from their diet, surroundings, and so much more.
The three layers of bioactivity
Substrate
This is the foundation of your ecosystem, and creating a proper bioactive substrate is essential. There are no two ecosystems with the same base, so a bit of research here can pay dividends down the line. Soil can retain moisture, helping with humidity. Different plants need different soil types and structures, and different viv inhabitants will also want different things.
Topsoil is a great place to start. Make sure it’s organic, or homegrown as chemicals in the soil can cause issues for years.
Now you need to look at the amount of moisture you want to be held, and the natural substrate in the wild. A beardie lives on sandy soil, even in the more humid microclimates, whilst something native to a rainforest floor will have a heavy organic layer and need a lot higher humidity. Mimicking the perfect habitat is especially crucial for species like isopods.
Most isopods need relatively high humidity, and there are a variety of things you can add to the soil to increase the water retention properties, such as coconut fibre, sphagnum moss, or leaf litter.
Aeration is also important in the substrate to prevent compaction and ensure healthy root development by allowing oxygen to reach plant roots and beneficial microbes.
Which brings us to our first tip. Leaf litter as well as being a great foodstuff for isopods, will also increase the amount of water retaining properties. Add in the nutrients that plants need, and you don’t even need to mix it in. The substrate should support plant growth by providing essential nutrients. As long as you have something that will help the leaves decompose, such as isopods and other organisms that break down organic material, you can just put a layer over the soil and let them do their thing.
Bioactive soil
There is very little that can make soil bioactive other than time. Generally, it’s the fungi, bacteria and other microorganisms that make a soil bioactive. These fungi and bacteria also serve as a vital food source for beneficial critters and soil organisms in the terrarium.
Microfauna, such as springtails and isopods, feed on organic debris and help break down decaying organic matter, which supports nutrient cycling and maintains the health of the ecosystem.
So for our second tip here is a way to increase the amount of these microorganisms. Use a variety of plants. Plant roots are teeming with all these essential life forms. Plants that have been grown in soil, and organically will have more than those grown hydroponically, or in intensive setups. So to take things a step further see if you can find plants that have been grown in a small nursery, or even by an enthusiast in their own home. Check your local marketplace to see what’s available.
Plants
There are a huge range of plants out there, many will be native to the area your vivarium inhabitants are originally from. But many will be too big for the size of the enclosure, and it's important to select plants that are safe and suitable for your pet, whether you keep bearded dragons, dart frogs, crested geckos, or other species. Each pet has specific requirements for plant safety and habitat design.
So third tip, you can plant something that is going to grow too big, with the intention of moving it out of the viv as a houseplant later, and then take cuttings from the original plant to keep in the viv.
For high-humidity vivariums, tropical plants are excellent options, as they thrive in the moist conditions needed by species like dart frogs and crested geckos. It’s well worth remembering that most aquatic plants are in fact only semi-aquatic, and are grown out of water with only their roots wet. In fact, a fair number of plants that are sold as aquatic are only able to survive underwater for a few months.
This means there are a huge number of plants that you can add to your set-up, they’re normally smaller than many house plants, relatively cheap, and available at many fish stores. They’re also not treated with chemicals in most cases, just ask for plants that are shrimp-safe.
If they have upright stems and the plant can stand up out of water it is suitable for a high-humidity vivarium. Plant consumption by cleanup crew or even your pet is a natural part of the ecosystem, helping to maintain balance and mimic natural environments.
Clean up crew
We’re clearly biased, but all cleanup crews should be based around isopods. The cleanup crew, including isopods, springtails, and sometimes suitable snails, is essential for breaking down organic waste in the vivarium. Isopods and springtails actively break and decompose organic materials such as leaf litter and decaying matter, playing a crucial role in breaking down waste and maintaining a healthy habitat for all inhabitants. There are a whole load of isopods that you can keep with something suitable for almost every enclosure you can think of, head over to our shop to see what we have in stock.
Maintenance and Monitoring
Maintaining a thriving bioactive terrarium goes beyond the initial setup—regular monitoring is key to ensuring your self-sustaining ecosystem remains healthy and balanced. Even though a bioactive enclosure is designed to mimic the natural world, with its own clean up crew, live plants, and carefully layered substrate, it still requires your attention to truly flourish.
Start by keeping a close eye on the environmental conditions inside your terrarium. Temperature, humidity, and lighting should all be tailored to the specific needs of the species you’re housing. Many reptiles, amphibians, and invertebrates have particular requirements, so use reliable thermometers and hygrometers to track these parameters. Proper lighting not only supports plant growth but also helps maintain the well-being of your animals and microorganisms.
The drainage layer and substrate layer are the foundation of your bioactive setup. Check the drainage layer regularly to ensure it’s not holding excess water, which can lead to stagnant conditions and harm both plants and animals. The substrate layer should remain moist but not waterlogged, supporting both the clean up crew and the roots of your live plants.
Observe your plants for signs of healthy growth—vibrant leaves and steady development are good indicators that your bioactive environment is providing the right nutrients and moisture. Similarly, watch your clean up crew in action; active isopods, springtails, and other small organisms are a sign that organic matter is being broken down efficiently, helping to recycle nutrients throughout the enclosure.
Routine spot checks and minor adjustments—like removing dead plant matter, topping up leaf litter, or tweaking your watering schedule—will help maintain the delicate balance of your bioactive terrarium. By staying attentive to the needs of each layer and the inhabitants within, you’ll create a suitable environment where your plants, animals, and microorganisms can truly thrive.
