A bioactive terrarium is completely different from more common, traditional terrarium setups. A bioactive setup is designed to be a living ecosystem with plants, small clean-up insects, and a substrate that breaks down organic matter (such as your reptile's waste) through biological activity. That's why these terrariums are called "bioactive." Putting everything together and making it stable is more challenging, but these terrariums are also more rewarding.
What Are Bioactive Setups?
Bioactive setups include substrates that have a high content of living organisms, including fungi, bacteria, and microorganisms, which feed on organic waste. Most include live plants, as opposed to plastic or artificial plants, to further enhance the biological activity in the setup.
The living organisms in the setup help break down waste and keep your enclosure clean. They also provide vital nutrients for your reptiles and amphibians, such as calcium and phosphorus, from the bacteria in their guts. This creates an overall healthier, more natural environment than if you establish a sterile terrarium for your reptile or amphibian.
A "sterile" terrarium - that isn't designed to mimic a natural environment - still has a ton of biological activity going on. It just isn't managed in the same way as a bioactive setup, where biological activity is the focus.
Necessary Equipment and Supplies
The supplies you need to create a bioactive substrate for lizards vary based on species, but the most commonly used materials include:
- Substrate, including soil, coconut coir, sphagnum moss, and bark chips
- Clean sand or topsoil
- Pea gravel or small lava rocks
- Live plants
- Isopods and clean-up crew
- Lighting and heating equipment
- Hygrometer and thermometer to monitor humidity and temperature
Before setting up a bioactive system, research the specific needs of your reptile or amphibian species and choose the materials accordingly.
Gravel and sand are not recommended as the primary substrate for a bioactive tank, as these are not suitable for clean-up crew insects and do not retain biological activity nearly as well as soil or suitable alternatives.
Most bioactive terrarium systems include a deep, layered substrate to allow for biological activity to occur. Plan to leave around six inches of space to build your various layers of substrate. You will need to add a drainage layer at the bottom, your primary substrate above it, and a topsoil layer or leaf litter at the top.
Organic topsoil is a great option - and is very commonly the choice for hobbyists setting up a bioactive terrarium - as it already has organic material present to kick-start the process. If you go with coconut coir without mixing in soil, your system will take longer to achieve biological activity. Coconut coir is a great option to include with organic soil, because it helps with drainage.
Biological activity requires moisture, and most bioactive setups are created to maintain high humidity levels. This is why it is so difficult to establish bioactive setups for species that do best in dry environments.
Isopods are a part of bioactive setups. These are the workhorses of your system, and include critters like rollie pollies (also known as pill bugs or woodlice) and springtails, which are favorites among hobbyists. These isopods live in and move through the substrate, stirring it up, and they eat organic waste to help break everything down.
You can also add earthworms to perform a similar task. Many setups use all three to accomplish a lot of biological activity in the setup. Most reptiles will leave these species alone, especially if they are well-fed. Your pet might consume some of your clean-up crew over time, however.
How to Set It Up
To set up the bioactive terrarium, take the following steps:
- Create the drainage layer: The drainage layer is the bottom layer on the terrarium. You can use lava rocks for this layer to prevent problems with over-watering.
- Add substrate layers: Mix 60% silica-free sand, 30% organic topsoil, and 10% coconut husk chips together to form the substrate. You can also use ReptiBark or something similar instead of coconut husk chips if you prefer. The deeper the substrate layer, the more likely your tank is to be successfu. Including the drainage layer, your substrate should be around six inches deep.
- Add the bugs: Once the substrate is added, you can place the isopods, earthworms, or Dubia roaches in the terrarium. You can choose one, two, or all three. These insects will help your terrarium be more self-sustaining.
- Scatter the moss and bark: Scatter the coconut coir, sphagnum moss, and bark chips along the top of the substrate. You can also use leaf litter for this purpose.
- Add the live plants: You can now add your live plants to the terrarium. Choose the plants based on your lizard species.
- Heating and lighting: You have developed the bioactive terrarium at this point. Once you get to this step, you can add the heating and lighting, and place your reptile inside to see how they do.
Once the terrarium is set up, it may need some help to get going initially. Once you have completed some troubleshooting, it will be self-sustaining.
You can add peat moss into your substrate mix - about 10% of the overall substrate - to help retain moisture. This isn't always necessary, however, depending on the ambient humidity in your area.
Benefits of Bioactive Substrates
Bioactive substrates are great for reptiles and amphibians because they provide natural sources of beneficial bacteria and nutrients. These microbes help keep your reptile's gut healthy by digesting food and regulating digestion. They also help regulate immune function by producing vitamins and providing an environment where good bacteria can thrive.
In addition to these benefits, bioactive substrates also create environmental advantages that promote habitat stability. They hold moisture better than plain sand or soil and make it easier for your reptile to burrow in. This helps keep humidity levels high in the enclosure while keeping temperatures low enough so that your reptile can thermoregulate easily.
Live Plants Help, Too
Adding plants to your bioactive setup is a great idea. They help absorb biological waste, and help your system mimic a natural environment. Because they consume biological waste, they work with your clean-up crew to improve the overall environment.
Live plants require light in the appropriate spectrum for growth. You can use a suitable reptile lamp that provides ultraviolet (UV) light in many cases, or you can buy a plant grow light that is appropriate for reptiles. You just don't want a light that adds too much heat to your system - make sure the temperature is stable within your reptile or amphibian species' range before adding your pet to the system.
You can place live plants in your substrate if it is suitable for that species, or you can pot them separately and bury the pot in your substrate. Both options work, but separate potting allows for more control.
In a regular, non-bioactive setup, you can typically maintain humidity levels just by misting with water. You might be able to get away with this method in a bioactive setup, but you'll have to be diligent to watch your system and monitor humidity levels.
Alternatively, you can automate this process. To do this, you need to buy a fogger, misting system, or even a waterfall element to increase humidity. You also need to check your hygrometer regularly to ensure humidity levels are optimal.
For tropical bioactive setups, maintain humidity around 50 to 60%. Even in an arid, desert-like bioactive system, ambient humidity should still be around 50%. In all bioactive setups, the bottom substrate layer needs to be kept moist at all times.
Species Best Suited to Bioactive Systems
Tropical reptiles and amphibians do best in bioactive setups. Reptiles that stay small, such as geckos and some lizards, as well as tree frogs, arboreal (tree-dwelling) lizards, and small snakes all do well in these systems.
Larger species, such as many lizards, most turtles, or reptiles that prefer drier environments, rarely do as well in these systems. Larger species will dig into the substrate and move plants around or destroy them. They also just take up more space and need larger environments. Any pet reptile species that disturbs the substrate can impact the effectiveness of your clean-up crew. The best-suited species include:
- Arboreal tree frogs: Various species
- Land-dwelling frogs: Poison dart frogs, packman frogs, etc.
- Geckos and anoles: Especially tree-dwelling species, mourning geckos, web-footed geckos, Standing's day geckos, green and brown anoles, etc.
- Small lizards: Most chameleons, blue-tongued skinks, uromastyx, etc.
- Small snakes: Western hognose snakes, corn snakes, garter snakes, green snakes, any arboreal snakes, etc.
All reptile and amphibian species can technically be established in a bioactive setup. Larger species just require a lot more space for the system to remain stable over time.
Wait at least one month before introducing your reptile or amphibian to the bioactive habitat. During this month, you need to monitor the enclosure for parasites and fungal growth. You will also want to address the following if they occur:
- Temperature: If plants are dying, check the temperature inside the habitat. Too much or too little heat could kill your live plants and clean-up crew.
- Lighting: Inappropriate lighting could affect your insects and live plants, and can even impact the overall wellness of your terrarium's ecosystem. A good grow light is necessary to prevent plants and insects from dying.
- Humidity: You should have a hygrometer to determine the humidity levels within the terrarium. If you do not have a sufficient amount of substrate, your tank may not reach the appropriate humidity level.
- Mushrooms or mold: If mushrooms or mold show up, your clean-up crew should take care of them. Do not remove them unless absolutely necessary.
If, after one month, the terrarium appears to be self-sustaining, you can introduce your pet. But you still need to closely monitor their health and the overall condition of the system. Watch out for strange growths, weird smells, dying plants, or anything that appears to be unhealthy.
To help your live plants grow, place shorter plants in open spaces, and keep your tall plants close to the tank walls.
FAQs About Bioactive Substrates
Bioactive terrariums are all about achieving balance. This takes some time. Check to see if you've addressed these common issues:
- How often should plants be watered? Most plants should be watered one to two times per week, but this will depend on the type of plants you have chosen, how they are planted, and the overall moisture levels.
- How often does the sphagnum moss need to be replaced? Sphagnum moss should be replaced once every two months to maintain a healthy bioactive environment.
- Does the bioactive terrarium need bugs? Yes, the insects suggested are detritivores - meaning, they eat biological waste and dead material - and help maintain an appropriate balance of bacteria.
- How often do you need to change the substrate? You don't need to change the substrate once the terrarium is balanced.
How can insecticides and herbicides be avoided? Following the purchase of your plants, remove them from their pots and gently free the soil from the roots. Run the plant under clean water. Then, allow the roots to soak for 10 to 20 minutes prior to planting in the terrarium.
Bioactive Systems Are Deeply Rewarding
Although a bioactive terrarium takes some work to get started, it has many benefits that can help your pet stay healthy and thriving. If you're hoping to mimic your reptile's or amphibian's natural environment, this could be the perfect option. Once it gets going, you won't have to do much to maintain it and you will notice your pets are happier and healthier as a result.