The dream of many amphibian and reptile hobbyists is to create a thriving, self-sustaining, maintenance-free ecosystem that houses both live plants and animals. With proper planning, it is possible to create a beautiful living terrarium that comes close to the dreamed self-sustaining system. Sometimes called a bioactive terrarium, beneficial microorganisms play a large role in the health of this type of setup and do much of the work involved in maintaining it for you. Unfortunately, these little creatures can’t do all the work, so I would like to take a moment to discuss some of the maintenance needed to maintain planted terrariums.
Definitions. First off, what is a terrarium and how are they different from other types of herp housing? Terrariums are miniature greenhouses. They glass enclosures that contain live plants. The addition of plants, which can help to breakdown animal waste, is the difference between a terrarium and your average reptile or amphibian enclosure. A vivarium is a terrarium that has been designed to house and accommodate the needs of animals. Generally, the focus of a vivarium is the animals that are being kept in it rather than the live plants. A paludarium, aqua-terrarium, or aqua-vivarium are all different words used to describe a terrarium or vivarium that is designed for semi-aquatic plants and/or animals and has a large water area to accommodate them.
In all of the above environments there is some maintenance required by the keeper. The amount of maintenance needed depends on the species being kept, the number of individuals being kept, the amount and types of plants, the size of the enclosure, the substrate, and other aspects of terrarium and vivarium design.
Waste Removal. The most frequent kind of upkeep involved in terrariums and vivariums, besides basic plant and animal care (feeding animals, regulating correct temperature and humidity, etc.), is removing waste from the tank. When keeping insectivorous reptiles or amphibians, leftover dead feeder insects can create a lot of waste. Dead insects often mold over in tropical terrariums and can become a source of unwanted waste, so remove them as soon as they are noticed. Fallen and rotting plants are another form of waste that is often overlooked. If a plant in the terrarium starts to rot or die it may need to be removed. A large dying plant in a small tank can create too much waste for the system to handle, however occasional fallen leaves and let to decompose on their own usually do not present a problem. Other common sources of waste that should be removed include accumulating animal feces, shed skin, and infertile eggs.
But don’t worry; this work is not entirely left to you. A terrarium that has been set up for a few months should have healthy populations of beneficial bacteria that help take care of the waste. Additionally, other good microorganisms and small helpful invertebrates can be introduced into a terrarium by mixing leaf compost from outside into the soil or substrate. Unwanted organisms can also be introduced from leaf compost along with desirable ones, so consider the risks before going out and grabbing a handful of leaf mold to toss into a tank. Pests include slugs, snails, and other animals that eat plants and reproduce easily.
Water Changes. Just like in a simple herp setup, water changes need to be done regularly. Water dishes are easy to change but often look unnatural in a terrarium. Instead of using a water dish, you may prefer to create a small pond or reservoir where water naturally collects in a lower part of the enclosure. This works well and looks more attractive than a water dish, but it’s important that this water is still partially replaced on a regular basis. When there is a large volume of well-oxygenated water, such in a paludarium, it can be best to rely on beneficial bacteria to control harmful waste in a similar way to that of an aquarium. In these setups, partial water changes should be done every two to three weeks. The use of a filter may also be helpful when a large volume of water is being used. When using small volumes of water, it can be more difficult to maintain stable conditions, and partial water changes may be needed as often as once or twice weekly. The addition of live aquatic and emergent vegetation can help control nitrates, and is a good addition to a pond in a terrarium or vivarium.
Glass. The appearance of a healthy terrarium can be ruined if the glass is difficult to see through. Water spots are a common problem and develop quickly if tap water or spring water is used to mist the terrarium. To help avoid this problem, use distilled or reverse osmosis water for misting. Condensation is inevitable and will always form on the front of the glass in tropical terrariums unless a large amount of ventilation is provided or the temperature on the inside of the terrarium is the same as out. Unfortunately, providing large vents or screen sections in a terrarium for ventilation or temperature control can also drastically reduce the humidity level, and may not be practical for some terrariums or vivariums. Algae and cyanobacteria (blue green algae) often wreak havoc on the glass terrariums, and may need to be wiped off regularly. You can use a razor blade to scrape the front glass of a terrarium every couple weeks in order to maintain good visibility. Do not use razor blades on acrylic because they will scratch it. Instead, use a paper towel or acrylic-safe algae pad to wipe the front of an acrylic enclosure.
Substrate Maintenance. Many people new to terrariums fear that the substrate needs to be changed regularly like it does in a simple setup. Fortunately, most well-planned terrariums do not need to have their substrate entirely replaced. The plants and microorganisms living in the substrate help breakdown waste and do most of the cleaning for you. In areas where large amounts of waste accumulate, such as a feeding area where insects are dropped into the cage or underneath a basking site, it may be helpful to scoop out the substrate and replace it every few months. Soil mixtures based off of coconut husk fiber can last years in a vivarium. Those based off of peat or fir bark may spoil faster. The substrate should never become waterlogged or completely saturated with water, so providing good drainage is key to a long-lasting substrate.
Use Your Nose. The smell of a terrarium is a good indication of its health. A healthy terrarium will smell fresh and have a pleasant odor, like the forest floor or a pile of leaves. A terrarium that has a bad odor when opened and smells like muck in a bog is not healthy and should have its substrate partially or entirely replaced. Not all terrariums can go for long periods of time without a complete substrate change. Those that house large reptiles or amphibians or contain a high density of small ones may accumulate waste too quickly for the beneficial critters to breakdown, and in this case the soil may need to be changed a few times a year to maintain a healthy environment.
To Conclude, terrariums and vivariums are more attractive than simple herp housing and can be less work to maintain. They are enclosed biological systems, and much of the cleaning that has to be done in more simple hygienic setups is instead performed by beneficial bacteria and other microorganisms. But this isn’t to say that terrariums and vivariums are maintenance free. There is still a fair amount of work that needs to be put into keeping one healthy and clean. Removing large amounts of waste, doing water changes, cleaning the glass, and partially replacing some of the substrate are the regular tasks that need to be completed in order to sustain a living terrarium or vivarium. When these are done on a regular basis, most terrariums and vivariums survive for years with minimal maintenance from the keeper.