----What is a Bioactive Substrate?
A bioactive substrate is any substrate that recreates an ecosystem essentially. For our purposes, it is in a closed system. Many keepers are making the switch towards it due to the natural and enriching aspects of it, though it's been around since reptiles and amphibians have been kept. This required a basic understanding of ecology of the species you would like to keep on it. Without this knowledge, you have nothing to base the substrate on as it will vary from species to species, and keeper to keeper.
For quite a while, it was restricted to only the more tropical species because most of the time, they needed or benefited from it. It was also a lot easier because due to the humidity, feces broke down quickly with the help of bacteria, fungi, and detritivorous insects, hexapods, etc.
Many breeders, more so in the Continental United States (though a few in Europe), have been using more minimalistic and sterile enclosures to keep dragons. Now, this does work very well as the animal is kept very clean through sterilization of all feces and surfaces in which bacteria can reside.
With this being said, bearded dragons like every organism on Earth came from the wild. This essentially means that bioactive (or naturalistic) substrates or enclosures can actually be artificially created with them in mind. You create a "self-contained ecosystem with its own inhabitants, food chain, nitrogen cycles, and climates." Essentially, you create a living thing. This will invoke bearded dragons to use their natural behaviors of burrowing, grazing, hunting, and thermo regulating.
This is not recommended for ALL keepers of bearded dragons because it can go wrong very quickly and you will end up sad and with a dying or dead bearded dragon. Consider this a warning before you begin creating it. Bioactive substrates do not ALWAYS look pretty, nor do they have to. They just need to be functional. They are not for the lazy people who do not want to clean their enclosures. Remember, if you do not clean a tile floor, you end up with a dirty floor. Ignore this, and everything dies within it.
If you do not feel like you can keep your dragon 110% healthy, then this substra....bearded dragons are not for you.
----Now a Few Fears That Many Keepers Can Think Of.
-Impaction is the collection of debris in the guts. The debris can really be anything at all, be it food, substrate, etc. Impaction is what is known as a secondary illness. This means that something in your husbandry must be wrong for it to happen. Of course, there are exceptions like feeding massive prey items, but generally speaking, it's a secondary illness. The ingestion of substrate while hunting WILL NOT be enough to impact a HEALTHY dragon. The key word is HEALTHY. A lot of dragons in captivity, believe it or not, are not very healthy.
To talk about a wild bearded dragon, s/he will likely have a large fluctuation in resources because they are constantly on the move to find food and shelter. Wild dragons, because they do not consume multivitamins, will often be deficient in vitamins and/or minerals. This is where they may consume the substrate to refill this. It's a natural instinct to do this. This means that our captive dragons, if deficient of a mineral or vitamin MAY eat the substrate openly, in which case, you should reconsider a loose substrate until the husbandry is fixed.
The metabolism and digestion of the debris depends generally on temperature and hydration. If dragons are not kept at the correct temperatures (generally, captive temperatures of around 90-100 may not be sufficient for digestion of large amounts of substrate), they will be able to pass them easily. However, it would also depend on the hydration level of the dragon. Around inanimate or indigestible objects, the body will create a mucus coat around it as to not tear the guts but rather let the object slide through easily without causing damage. This process is very water intensive, which means that your dragon needs to stay consistently hydrated all the time.
Bottom line: "Reptiles that are provided with varied diets, supplemented with calcium, multivitamins, and have access to UVB lighting and are kept at proper temperatures should not experience Impaction." (ZooMed).
-"Humidity will cause R.I.'s or Respiratory infections. Water bowls will cause RI's. Misting or spraying too much will cause RI's. Baths will cause RI's. They are desert animals and don't need water or moisture. False. All of it is false. All of this is just a misunderstanding (or myth) that gets passed along as an easier way of explaining. Bacteria, and in rare cases, fungal, cause RI's when inhaled and is exacerbated by heat and moisture.
Dragons live in arid to semi-arid woodlands and a range of other habitats in the wild. They experience large range of fluctuations in rH from 20% upwards to 80% with an average of 40-60% rH. Not to mention all of the large scale outdoor breeders in Florida raising dragons in 80% rH year round. With this said, dragons are pretty hardy and can tolerate a wide range of humidity quite well. I feel dragons should always have access to fresh water and if a water bowl is creating a humidity issue, then you really have a ventilation issue that needs addressing. Sterile enclosures with poor ventilation (and often times too cool of a temperature) has become a normal US breeder influenced environment. (Not to bash ALL breeders, just some of the "bad" ones). When you couple together a sterile enclosures with stagnant air, it becomes conductive towards fungal and bacterial blooms. However, keeping it completely bone dry is likely to cause problems for your dragon as well as the lungs struggle to stay moist, which compromises the immune system of your dragon.
All in all, humidity should not become a problem as long as the tank is kept at a proper temperature and is well ventilated utilizing cross vents preferably.
Here is a 30 year, month by month, 9am and 3pm climatology study to prove the wide range of humidity encountered in the wild. Http://www.bom.gov.au/watl/humidity/"
(Most credit to Derek Nye, a bioactive bearded dragon keeper. I edited very little of what he wrote.)
Another thing to consider is micro environments and micro climates. For example, a bearded dragon who has dug into the ground will likely experience a rise in humidity due to the moisture trapped into the ground.
So bottom line: keep the enclosure well ventilated utilizing cross ventilation and the dragons should not experience any respiratory issues.
>>Fungi, Bacteria, and Parasites.
-This ties in with what was discussed in the Humidity section as well. Naturally, a healthy soil will effectively counteract fungal and bacterial blooms creating a balance. With proper ventilation, these blooms are also going to be very few because they won't have the correct humid, warm, and stagnant environment in which they thrive in.
Again the dreaded Respiratory Infection is caused by bacteria and in rare cases, fungi. In a traditional sterile setup, the only way that bad bacteria are gotten rid of are by stripping the tank bare and sterilizing it. These setups are also generally very dry which can cause bacteria to go airborne and become inhaled and once proper conditions are met for these bacteria, the process of infecting begins.
Similarly, loose substrates or any porous substrate of any kind like reptile carpets, fake grass, play sand, etc., can trap a ton of bad bacteria that you do not want in it. This is why most keepers remove the entire radius around the feces to stop some spread of bacteria. In a Bioactive setup, you use good bacteria and other macro organisms to "battle" the bad bacteria and effectively stopping their spreads. Everything in nature has a balance.
It is recommended that the bearded dragon have a vet checkup with a fecal to rule out any parasites that the dragon may contain before being switched onto a bioactive substrate. Though animals that have a small count of parasites seem to do very well on it, you may want to kill all of them before beginning to stop any possible problems in the near future. The bearded dragon's immune system should not be compromised and be put on a bioactive substrate.
People also always ask me what it smells like. Simply, it smells like earth. It smells like I stepped into a nice and luscious forest. This is because dirt contain a bacteria known as Actinomycetes, which "crucial to the formation of hummus." These bacteria convert dead organic material and turning into peat, which then releases nitrogen and carbon. Because of this bacteria, the levels of bad bacteria may decrease once they rise. They also produce antibiotics, which further lower the levels.
Mold is also another problem that is also thought of. This is very simple to combat. There are very resilient hexapods called springtails. They even live in Antarctica. Their main food source is mold almost everywhere. They eat it very readily as will most of your other cleaners that are added to the enclosure.
And of course, like I said above, nature always has balance so not ALL of the bad bacteria are completely eradicated. However, we all know that in order to build your immune system, you must have a small amount of said bacteria or virus in contact so that your body may respond to the incoming danger. This idea is how shots work. They inject a small amount of the virus so that your body can learn how to destroy it. This can also work for a bearded dragon to build a much stronger immune system.
Another hobby we can learn from is gardening. Specifically in their composting or worm bin setups. These are very efficient ways to use cleaners to clean decaying waste, like feces, and return it into a highly rich source of nutrients. Many gardening forums may be an excellent place to learn from online if you would like to read further.
The desert portion of the bioactive hobby is slightly experimental. It isn't as settled upon like the tropical side of the hobby. Many keepers use various types of substrate that they think is the best. These may or may not work. It actually depends on your personal setup.
Because of what is mentioned above, I will tell you what I use to create my substrate.
My substrate consists of:
1) 50-60% play sand (silica free, made for children)
2) 30% organic no pesticide top soil
3) 5-10% coconut husk (grounded) and other misc. products like small wood chips
These three things are the main components to my substrate. The top layers have more sand than the bottom layers to accommodate both the dry and tropical cleaners that I have added to the enclosure. This also keeps the lower layers cool for any earthworms that are added. However, due to digging, lots of it is mixed up. So if you have a digger like me, it probably won't matter how you choose to layer it.
1) The play sand gives the entire thing the more dry part of the substrate as well as adding structure to it for burrowing and digging.
2) The soil generally will have a ton of springtails and Isopods in it already. It also likely will already be cycled with good bacteria if left outside. It also sustains plants, which I will cover later in the article. It also will hold more water for the tropical cleaners that are added.
3) The coco husk and misc. wood products lighten the load allowing it to drain quicker. These are generally also naturally mold resistant so that is a plus.
Again, my substrate may or may not work for you. So you may need to experiment a little bit with it to find your own balance of substrate.
I keep my lowest few inches moist to the touch so you can feel the moisture. However, I keep the higher layers cold to the touch but with no feel of being wet or soggy. This keeps my humidity down easily and provides a similar habitat to what you would find in a woodland area in Australia. I also add moist hides for my more tropical cleaners in the enclosure.
Another thing people ask me is where did I get my substrate. The best place in my opinion to grab the substrate is outside. No, not near your house, your backyard, etc. Grab your dirt from a place AWAY from any human structures, paths, etc. Also stay away from any water streams, ponds, etc. when collecting. Check the area for any feces as well. The sand can be purchased at your local hardware store. Rinse it to take out the dust. Coconut husk can be bought under a few branded reptile names, however, it could also just be purchased in the garden section of your home improvement store.
Now a common question is to use a drainage layer or not. I'm all for a small drainage layer. It is not technically needed because it should not be receiving excess amounts of water anyways. However, overwatering is very easy and if you over watered, you would need to likely replace your ENTIRE setup because soil gets soggy and anaerobic very quickly. It's a very good safety net and could only take .5-1 inch in your setup. As for what to use in your drainage layer, I use either LECA (porous, inert, clay pellets) or lava rock. The main thing you want to look for is an inert substrate. Gravel can also be used, however, it gets heavy, and doesn't absorb water like lava rock and the LECA.
Another option that would not add weight to your build would be plastic lighting diffuser or egg crate. It is a plastic grid with half inch squares. You can hold it up by zip tying it to itself, or a small amount of PVC tubing works fine. Give it a lot of support as it will be supporting a good amount of weight though.
People also will add leaf litter on the top. This serves three purposes really: to provide a food source for the cleaners, a shelter for the cleaners, and to trap humidity under the soil, again, for the cleaners mostly. It also reduces the chance that the substrate will be consumed by the dragon. As for what to use, most fruit tree leaves are fine to use and most trees that are not evergreen conifers are also safe to use. This is very general idea of what to use. I personally do not use it because I can cover those three purposes without them.
A few people have also asked me about how deep to make it. I recommend at the minimum, 6 inches. If you would like to have enough for a female to dig and lay infertile eggs, 12 inches. The deeper you have the substrate, the more biodiversity it can hold within leading to a much better bioactive substrate and will make the system less likely to crash and much more stable.
-----The Tank Setup
As most of you know, the minimum amount of space for a single bearded dragon is 36x18x18. Now this is definitely enough to do a bioactive enclosure in, however, if you can go larger, please do. The smaller the tank, the less the substrate, thus, the less clean housing. This means that if you do not have enough substrate, it simply won't work because the cleaners won't be able to keep up with the food amount. I recommend a 4x2x2.
Again, this part is a bit dependent on the owners themselves. Some people keep it at the 90-110 degree F range, some keep it between 100-130, some between 110-150, and some even much higher than that reaching the temperature of most monitor species. Now keep in mind, these are surface temperatures. This is also why I recommend a larger tank. I personally keep it in the 90-150 range in the indoor enclosure which is more enclosed utilizing a variety of surfaces from different rocks, wood, and the dirt itself to allow the temperature to change drastically in a small space. However, for my outdoor enclosure, measuring 12x2.5x2.5 feet, I allow the temps to go up towards what most people consider a bit crazy. Similar to monitor keepers, it is usually around 150-170 degrees F surface most of the time. Of course, because it is outside, it cannot be completely the same all the time. I do not let it pass this though.
Now you may ask me, â€œWell, Justin, why would we want to increase basking temperatures?" The answer is really simple actually. A higher temperature allows a dragon to boost its metabolism very quickly allowing it to digest objects and food items it would not be able to do at the normal 90-110 temperatures. For example, many keepers will begin offering mice (that are not pinkies and have fully formed bones and fur) to their dragons. Higher temps allows them to digest this very easily if given sufficient hydration. Also on top of this, a higher temperature combined with sufficient hydration allows a dragon to digest substrate quickly and with ease. It also lowers the humidity a good amount.
With these temperatures in mind, you also will want to keep the cool side the same around 75-80 degrees F. This will allow your dragon to thermo regulate their own temperatures depending on what they need or feel at the time. Again, we can't know what they are thinking, but we can provide options so that they can choose.
In my indoor tank, my relative humidity sits at around 30-40% during the day, but 40-60% during the night hours. It is perfectly normal for the humidity to rise during the night. Yours may be higher or even lower than mine, and that's perfectly fine. If you have any concerns, please re-read the humidity section discussing the risk of respiratory infections that is often feared among keepers.
Wooden enclosures should be waterproofed via a water based or reptile safe sealer. You will want to waterproof everything, including the ceilings, sides, etc. Some examples would be using polycrylic, polyurethane, drylok, or a fish grade rubber liquid or liquid pond liner. Follow the directions that are on these.
If using the fish grade waterproofing rubber liquid or liquid pond liner, you are good to go. However, if using the other three options I mentioned, you will also want to purchase a cheap pond liner. You want enough to cover the bottom and however high you want the substrate to be in your tank. Even though they are sealers, they actually will allow moisture through eventually as it ages. This will obviously cause the wood to rot and eventually give way to the thousands of organisms that were living inside. This is why a pond liner holding the substrate is highly recommended.
>Front Opening Enclosures
Now many reptile keepers will keep their dragons in front opening enclosures for ease of access for various reasons. Now obviously, it likely will not hold enough substrate to sustain the enclosure. This is where you either would want to push a ton of substrate towards the back hoping it won't get dug towards the front or purchase a cheap piece of acrylic or glass and silicone it in the front to hold the substrate back from the door.
-----Cleaners in the World
Micro and macro organisms are what make the substrate actually bioactive. These micro and macro organisms feed on the feces, detritus, decaying, and decayed materials in the enclosure, which is how you create a biological cycle in your enclosure. The feces becomes a large food source for all these organisms to consume. We, the reptile keepers, use this to our advantage.
Some examples of macro organisms would be a few of the following. Please note, you may not have success with ALL of these organisms, but I have used all of them with at least some success...some better than others.
1) Superworm beetles and their larvae
2) Mealworm beetles and their larvae
3) Lesser Mealworm beetle and their larvae
4) Dermestid beetle and their larvae
5) Crickets (common house species works fine)
6) Various species of roaches like dubia, hissers, etc.
7) Compost worms
8) Fly larvae or maggots (various species)
9) Earthworms. Red worms or African night crawlers will do better than the others.
10) Isopods (various species)
11) Springtails (various species)
There are a few more organisms you can use that I have never tried before so I will not speak for them specifically. Each of the ones I have listed above require different materials and climates to survive, so research what each one prefers and try to create microclimates to accommodate them. For example, Isopods are a terrestrial based crustacean which requires a higher humidity, but will do well lower in the soil and with a humid hide during the day.
Predator insects also can play a role in keeping pests like fungus gnats at bay. I personally have put a small wolf spider in my tank, which are perfectly safe. Of course, do not add anything that can harm your dragon. Use these at your own risk.
Plants are everywhere. Plants bring a sense of nature and beauty to any terrarium. Unlike the sterile terrarium, plants in the bioactive tank actually serve a large purpose. At the end of the cycle of the cleaners consuming the feces, the plants can then utilize the feces of the cleaners in order to use as a nutrient source like an organic fertilizer. Generally speaking, they shouldn't need external chemicals and fertilizers to live well.
As for what types of plants, you want the types of plants to be consumable by the dragon, replaceable, and able to survive the climate easily. These plants will be smashed, eaten, clawed at, and in any other way, damaged by your dragon and the environment itself. This means that the plant shouldn't be your prized bonsai tree that cost you hundreds of dollars. It needs to be expendable. Many people like to grow micro greens, which you can use as small, mini bushes for the tank. They also serve the benefit of being a good food source. Fast growing herbs are also decent to use.
Because there are thousands of plants that could actually be used, I will provide a link to a website with a toxic and non-toxic list. Most plants on the various food lists can be grown as well, though many of them will not survive well in the conditions of the enclosure.
Some examples that I have used before:
1) dracaena (some are toxic to small mammals in large amounts)
2) echeveria (common name: hens and chicks)
3) pothos (toxic to most small mammals in large amounts)
4) mint (spearmint specifically)
6) micro greens of collards and mustards
7) various types of grasses like wheat grass
Website: anapsid.org. (I am not sponsored or affiliated with this website or Melissa Kaplan.)