What is a bioactive terrarium?

A bioactive terrarium is set up to replicate a reptile’s natural ecosystem, in which waste material is broken down by specialized organisms and recycled into food for the plants. Once functioning, bioactive enclosures rarely need cleaning out.

Is a bioactive terrarium right for me?

I believe that bioactive terrariums can be great for anyone who’s wanting to add a little life to their reptile’s enclosure. As I’ll discuss later, it’s perfect for lazy people like me who hate cleaning since there’s very little upkeep involved after the initial set up. If you’re squeamish around bugs, it may not be for you, but hopefully you’re past that point if you’re caring for a reptile.

Bioactive terrarium pros

• Little to no cleaning
• No feces to pick up = no smell
• Encourages instinctive behaviors such as burrowing and hunting
• More naturalistic appearance
• Plants and natural substrate holds in humidity
• Soft substrate is easier on reptile’s joints than paper towels

Bioactive terrarium cons

• May be costly to set up
• Potential for pests/unwanted bugs
• Cannot be sterilized – not suitable for ill pets or those in quarantine

How to set up a bioactive terrarium

Supplies:

• Tank
• Drainage Layer
• Substrate
• Wood, ledges, and hides
• Plants
• Clean-Up Crew

Step 1: Choosing the correct tank

Depending on your reptile, your bioactive enclosure may differ from the ones described here. Some reptiles such as my crested geckos are tropical and require a vertical tank, while other reptiles such as bearded dragons prefer more arid, horizontal tanks. It is important to do research on your reptile’s specific needs before setting up a bioactive tank. Remember- improper husbandry is one of the leading causes of health problems for exotic pets, so I cannot stress the importance of ensuring proper lighting, heat, and humidity before getting fancy with a bioactive enclosure.

Step 2: Drainage layer

A drainage layer is placed below the soil in a vivarium, allowing excess water to drain away from the rest of the enclosure. I used specially-made clay balls but you can also use lava rocks or gravel. I personally like using clay balls because they hold the moisture well and are much lighter than gravel.

Step 3: Substrate

Depending on your reptile, your substrate will have different properties. I will be discussing substrates better suited for tropical species, so if you have a reptile more suited for arid environments, keep in mind that your terrarium may look much different.

Forest set-ups should have a spongy substrate that holds in the humidity well. The mix should be free enough to allow burrowing but firm enough to hold plants securely. Leaf-litter is encouraged for the top as this provides great protection and nutrients to your clean-up-crew. I chose to use HF Premium Tropical Substrate sold by Houston Frogs, but there are many other choices available.

Step 4: Wood

Next comes the backbone of the terrarium- add whatever sticks, branches, logs, bark, rocks, or hides that mimic your reptile’s natural habitat. Since crested geckos are arboreal, vertical branches worked best for this tank, but a nice horizontal log would work nicely for a land-dwelling bearded dragon. Pro tip: Coconuts shells make great hides for smaller reptiles – my geckos love them with a little sphagnum moss inside!

Step 5: Plants

Depending on your reptile enclosure, some plants will do better than others. Not only do you have to worry about the humidity, temperature, and lighting restrictions, but also your reptile’s weight and activity. My ball python is much heavier than my two crested geckos, so the plants in her tank needed to be much hardier.

Some common plants include-

1. Pothos – These are relatively strong and can be in a variety of ecosystems. I’ve seen pothos planted in all types of soil, sometimes even just in water. However, pothos does not do well in intense heat so I would keep it away from any heating pads or lamps.
2. Epiphytes, or air-plants: These are great for humid and arboreal tanks like the ones that crested geckos have. Since they do not need soil, you can attach them to branches higher up in the tank. Many of them absorb water from the air or collect rainwater in their leaves such as bromelaids.
3. Croton: These plants are pretty sturdy are great for adding a splash of color to your terrarium!
4. Snake plant: I highly recommend these because they are one of the strongest and tallest plants I have in my terrariums. I always see my ball python and geckos climbing on them!
5. Moss: Whether it’s Spanish moss, sphagnum moss, sheet moss, pillow moss, or any other variety, many people like to add moss to their vivariums to add to the natural “forest” look!
6. Bamboo: These are great additions to my crested gecko tank because they easily grow tall and fill up the vertical space!

Step 6: Clean-Up-Crew

Your terrarium’s clean-up crew, otherwise known as CUC, are the essence of a bioactive environment. These invertebrates keep the enclosure clean, recycle waste, and turn it into nutrients that plants can use. There are many types of CUC, so I will just go over some basics.

Isopods: A.K.A. Rolly-polly, woodlouse, or pill-bugs, are detritivores, which means they feed on dead and decaying materials, including feces. They come in many varieties and colors, which you can see in a beautifully designed poster here.

Springtails: These are closely related to insects and feed on fungus and decaying plant and animal matter. I keep a culture of springtails in a cup with charcoal, water, and baking yeast. Every few days I sprinkle some springtails in all of my terrariums to ensure that all fungal and mold growth is taken care of.

Superworm beetles: These are hard-shelled and produce a defensive odor when threatened which prevents them from being eaten by most exotic pet species. The beetles are great at removing feces and breed readily, producing superworms which my geckos love to hunt at night!

Some great links to get you started:
The Bio Dude – This website has an amazing selection of substrates, plants, lighting, CUC, and bioactive kits that are already categorized by the different types of reptile ecosystems.
Josh’s Frogs – In addition to selling awesome reptiles and amphibians, this website has a great collection of insects, feeders, and bioactive bundles! It also has great how-to guides and videos if you’d like more in-depth information about bioactive vivariums.
Houston Frogs – This website has a ton of cool CUC and DIY bioactive kits available, especially if you’re interested in frogs! You can even buy pre-made terrariums if you don’t want to get your hands dirty.
Reptile and Amphibian Bioactive Enclosures Group – This community on Facebook is great if you need ideas or have questions.