Bio-Active Terrariums|Revolutionizing Herps Again
Authored by Jeremy Kosonic Herpetoculture Canada
*Note from the Editor: Bio-Active seems to be on the forefront of herpetoculture lately. This is a subject which is near and dear to me as I came into herpetoculture at the tail end of the time when the forbearers of herpetoculture were creating ‘Bio-active’ terrariums and the proverbial ‘rack’ was virtually unheard of in the industry. Philippe de Vosjoli was and still is to my knowledge a pioneer in the field of Bio-Active Vivaria. Mr. de Vosjoli referred to reptiles as “Living Art” and the Bio-Active set-ups are the best way to showcase our incredible pets. Welcome to Jeremy one of our newest authors!
Are you tired of using paper towel and Chinese food containers in your setups? Are you tired of constantly replacing paper and stressing out your animals? Are you wanting a display showcasing a little slice of nature for your reptile/amphibian?
Look no further, Bio-active vivaria are for you! This is by no means a complete guide to all things bio-active, but hopefully it gives you a good head start.
What is Bio-active
Now, I’m sure the first question you are asking yourself is, “What is bio-active?”. Well, put simply, bio-active (short for biologically active) means that the soil is “living” and contains microfauna (invertebrates), fungus, and bacteria, all of which aid in the breaking down of waste. Before you get worried about having bacteria and fungi in your tank, not all of these are bad. Both are critical parts to an ecosystem, and help break down the waste, converting it into energy for the plants. So essentially, you are creating a mini ecosystem in your tanks. Now this is not a self-contained ecosystem, as you still have to do (minimal) maintenance, but it is probably as close as you are ever going to get.
Why Bio-active?
So now that we know what bio-active means, I’m sure you are asking, “Why?!”. Well, let me tell you! Bio-active setups initially take a little bit more effort to set up than the Spartan method many still use; but in the long run, it will cut down on the maintenance you need to do. If done properly, you will virtually never have to clean waste again. Some people have been able to maintain setups that have lasted 10+ years, and haven’t even changed the soil! This means no more changing paper a couple of times a week, no more worrying about the waste building up in the enclosure and your animal getting sick; this type of setup can break down waste in a matter of days, sometimes less.
From the beginning (Where to start)
The first thing you need to do before starting the vivarium is to identify the species, and where they are found in the wild. Are they found in sand dunes in North Africa or Vietnam? Or are they from the deep, swampy parts of the Amazon or Congo? Research the area a bit, try to find habitat shots, weather and climate info, soil info, anything that will help you design the tank to fit the needs of the animal(s). Once you have the information you need, you can start planning! These are just a few ideas to possibly get you started on planning the vivaria:
Arboreal – This is pretty straight forward, depending on where the species comes from. You can pretty much go as elaborate as you want with arboreal setups. Epiphytes, epoxy branches, Tree Trunk 
Madagascar Blue Iguana (Oplurus fierinensis)
Terrestrial– This usually has to be one of the more specific/ planned set ups, as you need to be able to create near-perfect micro-habitats for them. However, just as much can be done with this type of setup. More attention to soil should be used when making habitats for terrestrial species (see soil section below). Just be sure you don’t waste too much floor space with a water feature
Rupiculous– It’s a little harder to make this type of setup completely unique, as you are basically making a tank full of rocks no matter what. However it is possible, especially if your species is found in tropical habitats. Lithophytic (rock-dwelling) orchids
Semi-aquatic– The benefit to this type of setup is you can essentially have two elaborate setups in one. The terrestrial portion can be planted with lots of mosses
Fossorial/ Semi-fossorial– These types of setups are usually best when kept simple, as fossorial species often dig under objects, making them fall, sometimes crushing them. If you want to make this types of setups more elaborate like those previously mentioned, make sure any heavy objects are somehow secured to the bottom of the enclosure (Aquarium Silicone
Cage size
This will obviously depend on the species you are planning on making it for, and while it may sound very cliché, Bigger really IS better. While possible, it is much harder to have a sustainable microfauna population (as well as a proper temperature and humidity gradient) in, say, a 10 gallon than it is in a 120 gallon. Bigger enclosures will not only look more aesthetically pleasing and support more life, but it will also allow the animals to move around freely, giving them plenty of things to do and lots of enrichment. If designed properly, and their microhabitats have been achieved, no species (whether it’s 1” or 10 feet) will feel uncomfortable or stressed out in a large enclosure. In fact, they will likely do even better in a larger enclosure. Our awesome *Sponsor Zoo Med
The Dirt on Soil
Desert/Savannah soil mixture
A common misconception with bio-active vivaria is
“You can simply mix some topsoil and sand together in varying amounts, add leaf litter/bugs/plants, and you’re done.”
This is not the case. This mix will decay quickly and become very compact, not providing much surface area for bacteria, fungi, and microfauna. The soil should be designed to last decades, and decay slowly.
To me, the soil is the most important part of the habitat. It is what holds the whole thing together. It supports the plants and gives them nutrients, it gives microfauna a place to live and breed, it holds humidity, and most importantly, gives reptiles a place to burrow. Without soil, there basically wouldn’t be life.
Now, unfortunately I have to mention it, because I just know some of you out there are thinking about it.
If your animals are healthy, and the husbandry is correct, your animals will NOT, I repeat, NOT get impaction from this type of set up. Get that word out of your head now before continuing on, and while at this point. It is very unlikely and is a direct result of improper husbandry 99.99999% of the time.
False bottom
Before placing your soil in the tank, the first step is to put a false bottom down. This step is not really needed for drier environments, but is a necessity for more humid, wet environments. The purpose of a false bottom is to keep the soil out of the water that pools in the bottom of the enclosure after misting, to prevent anaerobic bacteria to build up, creating a septic state. There are multiple ways of doing this including plastic light diffuser, gravel, or expanded clay aggregate. A quick search on any dart frog forum (or our own article Dart Frogs and their Vivaria) will show you the many ways to create a false bottom.
Soil basics
While soil is a complex subject, In this article I’m going to “simplify” it a bit, to make it easier to understand and applicable to herpetoculture. There are 4 main ‘ingredients’ in soil; sand, silt, clay, and organic matter. This section describes the differences, as well as the benefits of each, and why they are useful in vivaria.
Sand
Size: 0.0625 mm to 2 mm
The most stable ‘ingredient’ in soil, sand is essentially small rock fragments usually made of quartz which is created by chemical or physical weathering of rock. It aids in aeration, drainage and over all stability of the soil. Sand prevents the soil from becoming too compact, which could lead to a swampy effect being created in the vivarium.
Silt
Size: 0.0039 to 0.0625 mm
Also a product of chemical or physical weathering of rock, Silt is in between sand and clay. It has less water-holding capabilities than clay, but is far better at holding burrows/shape than sand. Because of this, I like using silt as a large portion of many desert/arid mixes as it hold burrows well, without becoming rock hard when dry like clay does.
Clay
Size: <0.0039mm
Usually formed over long periods of time from the chemical weathering of rock. Clay is a great thing to add to the soil, as it not only helps hold burrows, but it also holds onto nutrients, slowly feeding the plants, instead of having it all leach into the drainage layer. The easiest clay to find is Sodium Bentonite, also known as modelling clay, or cat litter (if you use cat litter, make sure it is unscented, non-fired). Another relatively easy to acquire clay is Hydrous Aluminum Silicate, often sold as Redart Clay™. Both are easier to mix if mixed with water first, as it cuts down on the dust (I recommend a dust mask when working with the clay, for safety reasons). Another good choice for clay is calcium bentonite. Although generally far more expensive, in theory, the calcium in it will provide a source of calcium for the reptiles either through accidental ingestion, or through the microfauna/feeders eating it, transferring it to the animal.
Organic matter
Size: 0 to ∞
Organic matter can be anything that was once living. From leaf litter, to moss, to sticks, to grass, to decomposing animals (though I wouldn’t necessarily suggest mixing dead animals into the soil). Organic matter provides nutrients to plants/microfauna as it breaks down, and encourages things such as fungi, bacteria, etc. to populate the tank, making it more biologically active. The amount of organic matter in the soil mix depends on the environment, and where the animals are found. For example, tropical environments would require a high percentage of organic matter, while something such as dune species, would require essentially no organic matter whatsoever.
East African Spiny-Tailed Lizard (Cordylus tropidosternum)
How to choose
As previously mentioned, the soil mix you use depends on the species, and where they are found in the wild. Are they found on the forest floor in the Amazon, where the decay rate is high, and it rains frequently? Or are they found in the Savannahs of Africa, where they experiences long seasons of drought, and the decay rate is low (therefore having very low amounts of organic matter in the soil)?. These are mixes I’ve used with success, and would highly recommend. Of course, they aren’t the ONLY mixes you can use, but it’s a start.
Dune species
Coming from sand dunes, there really isn’t much choice when it comes to this. A deep (8″+) layer of sand works well, with the bottom 1/3 or so kept moist for the animals to have a humid place to retreat to, as well as a source of water.
Savanna/Grassland species
Generally experiencing long seasons of drought, with little organic matter, I use the following mix:
4 parts Crushed Stone Dust or Decomposed Granite
2 part silt or clay (whichever is more easily accessible to you.)
4 parts sand
0 – 1.5 parts organic matter*
*This would depend on what plants are being used. I usually use dried grass as the organic matter for Savanna tanks, as it is closer to what it would be in the wild.
Temperate
3 parts topsoil
1 part sand
2 part crushed leaf litter or fir bark
Caribbean
1 part topsoil
1 part sand*
1 part fir bark or crushed leaf litter
*1 part Aragonite sand can also be added for species found closer to the ocean, however it is not an important part of the mix and is more of an aesthetic addition.
Tropical
Mix 1
2 parts cocofiber
1 part charcoal
2 parts orchid/fir bark
1 part turface
2 parts crushed leaf litter
Mix 2 – ABG (Atlanta Botanical Gardens) Mix
2 parts tree-fern fiber
1 part peat moss
2 parts cocofiber
1 part charcoal
2 parts orchid bark
Mix 3 – Clay Soil
Arboreal/Rupiculous
These two are lumped together, as the soil for both of these completely depends on the habitat. The above mixes work well for any of the habitats. The main focus for arboreal/rupiculous species, is providing enough rocks/branches. For rupiculous species, make sure you provide lots of rocks. Some species may even require having essentially a large rock pile in the enclosure. For arboreal species, provide lots of horizontal/diagonal branches for them to climb, bask, and explore.
Plants
Plants are such a huge topic, that it may be best left for a separate article. However, Here are a few plants that would do well in each of the environments.
Sand dunes/ Desert/ Savannah/ Scrub
– Aloe spp.
-Haworthia spp.
-Pennisetum setaceum
-Opuntia ficus-indica
-Panicum repens
-Adenium obesum
-Euphorbia spp.
-Boscia senegalensis
-Cenchrus ciliaris
-Aristida pungens
Tropical/ Subtropical
-Calathea
-Peperomia
-Episcia
-Neoregelia
-Rhipsalis
-Spathiphyllum
-Maranta
-Anthurium
-Pleurothallis
-Bulbophyllum
-Pothos
-Philodendron
Caribbean Dry forest
-Rhipsalis
-Tillandsia
-Hylocercus
-Epidendron
-Mandevilla
-Cereus
-Neoregelia
Background
To make the most of the space available in the enclosure, a background should be used. Whether it’s just on the back, or on the back and sides, a background will not only provide a more naturalistic habitat, but it will also provide more climbing and planting space. There are many different designs; from using pressed cork board to preformed epoxy rocks (such as those available at vivariumworks.com or Universalrocks.com). You can also create your own background with materials like Styrofoam, grout/drylok, and acrylic paint. The sky is the limit when it comes to what background you use. Be sure to take their habitat into consideration when designing it though.
Microfauna
The most commonly used microfauna are Isopods (Trichorhina tomentosa, Porcellio scaber, and Porcellio spinicornis being the most common) and Springtails (Collembola sp., Sinella curviseta, Entomobryomorpha sp., etc.). However, many other invertebrates can be used, including mealworms (Tenebrio molitor), Superworm (Zophobas morio), as well as various roach species and Blue Death Feigning Beetles (Absolus verrucosus).
Conclusion
This may all seem a little intimidating at first, but once you get the hang of it, it is very easy to understand and plan. Hopefully you found this article useful and will consider switching your animals to bio-active!