# Vivarium 101



## Broseph (Dec 5, 2011)

*Vivarium 101 *

The purpose of this article is to provide a general overview of a poison dart frog vivarium, serving not as a strict recipe, but as a resource to guide a keeper toward the best decisions for their frogs. Species specific information should be considered, and is available in the corresponding care sheets, which can be viewed here.

The core of the decision tree is balancing the aesthetic and spatial desires of the keeper with the actual needs of the frog, and should tip heavily in favor of the frogs. The true art of vivarium design is presenting an interesting and visually appealing living system that meets all the needs of its inhabitants.

*Basic Needs *

Putting aside all the fancy words, design concepts, and lecturing, the most important housing needs of a poison dart frog are usable space and temperature/humidity gradients.

Usable Space
All species of poison dart frog use both horizontal and vertical space in a vivarium, and need enough room to forage, exercise, and eliminate. When housed as pairs or groups, frogs need room and visual barriers to escape one another -- a social gradient.

The term “usable space” acknowledges the idea that the entire 3-dimensional aspect of a vivarium needs to be considered, and should be intentionally utilized in the design of a dart frog habitat. A thick layer of leaf litter in the substrate multiplies the usable surface area of the floor. Background and hardscape components provide permanent structures in the vertical dimension. Plants bridge the gaps as an ever-changing aspect of usable space.


Temperature/Humidity Gradients
A precise singular prescription for temperature and humidity is to be avoided, and frogs thrive when given the opportunity to thermoregulate themselves. To support this opportunity, we provide a gradient: a range of safe temperature and humidity choices within the vivarium. Room temperature, lighting, ventilation, misting, and vivarium contents (substrate, plants, etc.) are all variables in this equation.

Since different dart frog species have slight but important differences in temperature and moisture needs and tolerance ranges, referring to the care sheets and keeper recommendations for each species is recommended.


*Enclosures *


Generally speaking, an 18” cube is the absolute minimum size vivarium for a pair of dart frogs of any species, and a larger space is recommended. A larger vivarium offers the best opportunity for a keeper to provide temperature, humidity, and social gradients, and will be utilized by even the smallest of frogs. Taller vivaria are much more easily landscaped for the benefit of the frogs, and every species of dart frog in captivity will use as much height as is provided, so long as the space is designed to accomodate the distinct movement patterns of the species kept.


Glass enclosures are typically used, whether commercially purchased or custom made, and a front-opening feature is advantageous for long term use and maintenance.


Ventilation is absolutely necessary. A humidity gradient is impossible to achieve in a glass box without proper ventilation, and neither frogs nor plants will thrive without fresh air. At minimum, a 2” strip of fine mesh should run along the top of a vivarium, and multiple height ports of ventilation provide even better air exchange. In the unlikely event that too much air exchange is occurring, ventilation can always be occluded, but rarely the other way around.


A means to drain excess water should be provided, and can be accomplished with a bulkhead drilled into the glass, or an inconspicuous place for a siphon tube to be used intermittently. A bulkhead is the best insurance policy, as excess water will passively take care of itself, and is practically mandatory for automated misting. Glass drilling tutorials are available in the DB archives.
* Vivarium Floor *

The bottom layer is typically a “false bottom” where water can drain through the substrate and a water table can fluctuate while buffering the rest of the vivarium. This can be accomplished using egg crate and screen mesh (landscape fabric should be avoided as it may not allow drainage as well as screen mesh). Alternatively, filter mat material such as Matala can be cut to size and covered with mesh. Both methods work well to prevent water from wicking into the substrate, and can accomplish their purpose with less than a couple inches of vivarium height.

Historically, a layer of lightweight expanded clay aggregate (LECA), pea gravel, or the like was used as a base layer for the false bottom. Such methods require a very large “air gap” between the water table and substrate in order to prevent saturation, and consume significant height space in a vivarium.

Euro-style vivaria feature a sloped glass or plastic false bottom where water can drain into a trough-like feature, and require no additional construction work. InSitu is one builder of this style of vivarium.


Above the false bottom is the substrate, which serves as a media for microfauna growth and plant rooting, and can vary from half an inch to several inches in depth. Historically, a soil type substrate in the form of ABG was used. ABG (or very similar) is coarse, airy, and relatively long lasting, but must not be allowed to become saturated, else it becomes a smelly, toxic anaerobic mess. If one insists on a soil type substrate, ABG is a proven recipe with few alternatives.


Many keepers find an inert substrate to be preferable, such as pea gravel or calcined clay (Turface, etc.) which will not break down over time, affords excellent drainage, and satisfies the needs of most vivarium plants and microfauna. Small pockets of ABG can be used with a clay substrate if desired, but combining the two into a homogenous mixture defeats the purpose of each.

A calcium-bearing clay substrate can also be used, alone or combined with a calcined clay, and is an unfired clay product. Unfired clay will fall apart if overly saturated and can become brittle if cycled between wet and dry extremes, but will remain perfectly stable in a properly designed vivarium. It may offer nutritional benefits by imparting calcium and other minerals to the vivarium’s microfauna, and the interface between decaying leaf matter and natural clay is excellent microfauna habitat.


Atop the substrate sits perhaps the most important component of a poison dart vivarium; the leaf litter. Naturally fallen, dried leaves of varying sizes should cover the majority of the vivarium floor, and should be at least a few layers thick. The best leaves are robust and slow decaying, such as live oak and southern magnolia. The leaves of most hardwood trees have been used successfully by keepers; if in doubt, check the archives using the search function to see if the species in question is suitable.

The topmost layer of leaves should be allowed to dry between misting periods, and is one of the best indicators of proper humidity levels. Poison dart frogs do not appreciate constant wetness and will deteriorate if kept overly wet. The dry area allows them a chance to thermoregulate via evaporative cooling, prevents conditions like “foot rot,” and shelters microfauna populations below.

The bottommost layer of leaves interacts with the substrate and slowly breaks down, as one sees in a natural environment. This area is prime microfauna habitat, and remains fairly moist. Should the frogs desire more moisture, it can always be found at the bottom of the leaf pile. Misting can cease for days and the combination of proper leaf litter and a false bottom is all the moisture the vivarium and its inhabitants need.

Interrupting the interface between decaying leaves and substrate with a layer of long fiber sphagnum moss is an outdated and improper method. It negates the functions of the entire substrate system, mostly by holding too much moisture. Dart frog vivariums do not need a layer of sphagnum moss to "maintain humidity".

Leaf litter also is a major contributor in the fight to create usable space. Floor surface area is multiplied by every layer of leaves, and by offering constant shelter opportunities, encourages dart frogs to boldly explore and forage.


The vivarium floor need not be flat, and can be contoured with false bottom materials, substrate, and/or leaf litter. Such contours are visually pleasing and offer breaks in line of sight for the frogs.

Additional floor-area contouring can be accomplished with various types of woody rubble such as cork rounds and flats, and can help connect the floor to the background both visually and functionally. Perhaps paradoxical to the new keeper, more hiding places typically lead to bolder frogs.
*Vivarium Background*

Pages could be written about various methods for vivarium backgrounds and so-called hardscaping, but the goal is to provide as much usable space as possible. Tree fern panels, polyurethane foam, silicone and soil, cork bark mosaics, etc., all serve to create vertical space for frogs and plants to occupy. Links to many useful threads can be found here.


Varying angles of branches and woody rubble provide surfaces more usable than sheer vertical faces, and help fill the negative space often seen in the middle of a vivarium.


Long fiber sphagnum moss rears its head again, and while small amounts can help epiphytic plants root, excessive amounts draped over the hardscape only serve to hold too much moisture.


The hardscape of a background and branches, combined with plant growth, inevitably creates shaded spots on the vivarium floor. Such a thing seems like a downside, but these shaded areas in the leaf litter provide a cool spot for our temperature gradient, and once again encourage the frogs to be bold and visible to the keeper.


Many types of wood are useful for dart frog vivaria (though those that decompose quickly are less suitable), and a variety of seed pods are available to provide shelter for the frogs and visual interest for the keeper. Some useful types of both are discussed here.

*Water*

Misting helps water move through the vivarium. It flushes waste products down to the substrate layers and offers stimulating daily changes in humidity and temperature. Whether by hand or automation, misting is an integral component of a dart frog vivarium, but specific needs can vary wildly depending on temperature, ventilation, enclosure size, and vivarium design.


Water used for misting or spot watering plants is typically distilled or reverse osmosis in origin. Distilled/reverse osmosis water can be considered practically isotonic to tap water, biologically speaking, and will not harm healthy plants and animals. The trace amounts of dissolved solids in tap water (and most bottled/"spring" water) can cause water spots on glass and leaves via misting, and eventually accumulate in a vivarium to a point where salt creep can be observed on hardscape. Excess minerals from tap water can also build up in substrate, to the detriment of the plants.


Water features, with very few exceptions, are made for the enjoyment of the keeper to the detriment of the frogs. In a closed system, water wicks via capillary action across the entire vivarium. It soaks every component; rapidly rotting wood structures at best, and turning the substrate into a toxic anaerobic mess at worst. The frogs have no humidity gradient and are unable to thermoregulate and escape bacterial infection. Moving water is especially impossible to contain.


The use of foggers only provides visual interest for the keeper as well, and saturates the vivarium air with humidity with none of the benefits of actual rain fall. Foggers are not a substitute for misters, and are best omitted from dart frog vivaria.


Fertilizer is not needed in a functioning vivarium. Occasionally, a planted soil-less vivarium without frog inhabitants may need a light fertilizer if plants show signs of deficiency. An organic fertilizer at quarter to half strength strategically applied to individual plants can be helpful in such a situation. 
*Plants*

Live plants in the vivarium help process waste, move water, and provide ever changing usable area for the inhabitants. Artificial plants meet few of these criteria, and in fact can be injurious to the delicate skin of a dart frog.


Plants are chosen for their natural tendencies, and no amount of pruning or training can correct an improperly chosen specimen (though pruning will always be a recurring vivarium chore). As such, it is important to choose plants that impart benefits to the frogs such as sturdy leaves for usable space, and avoid dangers such as sharp spines. Water-holding bromeliads provide excellent breeding sites for many species and should be especially considered. Plants are best chosen to provide usable space and surfaces for the dart species being kept. Consider the size and lifestyle of the frog species when choosing plants.


Plants are an important aesthetic component of a vivarium, especially as they overgrow hard structures, and artistic design elements can be employed. The pursuit of yet another rare miniature orchid or epiphytic fern can become an addictive component of the dart frog hobby- beware.


The natural tendency of a plant is to grow upward and create a canopy in the vivarium. This makes for beneficial shady spots in the leaf litter, allowing cool temperature retreats and a sense of security which emboldens frogs. As such, one should not strive to fill the floor with “foreground” type plants, and a staggered stadium effect from the front to back of a vivarium is a visually stale recipe for rarely seen frogs.


Moss will often appear spontaneously in areas of the vivarium that offer ideal conditions; bright light and constant moisture, or it can be directly planted by the keeper in such spots. It should be considered an accent for the keeper’s enjoyment as it offers nothing of value to the frogs. In fact, if an entire vivarium is well suited for moss growth, it is not suited for poison dart frogs.


It is advisable to disinfect all plants (and anything that is at all moist, including rocks, wood and substrate) before introduction to the vivarium to reduce the risk of introducing frog pathogens, plant pests, or microfauna predators. Bleach dips are a common protocol for plant disinfection (link, link, link). Wood is much harder to adequately disinfect, and so using wild collected wood is not always a simple practice.
*Lights*


Poison dart frogs are diurnal creatures that appreciate an appropriate day/night cycle. Outside of this need, light choices are primarily driven by the dimensions of the vivarium and the needs of the plants. LED’s are most commonly used and are widely available. Recommendations can be found on the forum and from manufacturers, and lighting choices for moderately sized vivaria are straightforward. Especially tall enclosures require special considerations, such as beam angle and bulb placement for plant growth at all heights.


All light fixtures produce heat, and this should be considered in the vivarium. With typical LED choices, the heat is mild and helps create the thermal gradient. If the ambient temperature is high enough that a moderate LED fixture is overly heating the vivarium, the ambient temperature is too high.
*Microfauna*

The term "microfauna" denotes the tinier animals living in the vivarium system; mites, springtails, isopods, nematodes, etc. Some are intentionally introduced, while others find a way.


Springtails and isopods are usually introduced to help cycle nutrients and provide foraging for the frogs. Their role as “cleanup crew” may be overstated, but they are one of the only safe and helpful ways of adding biodiversity to a vivarium. Many species are available, and individual keepers may find particular species thrive in their local conditions compared to others. The larger isopod species are often discouraged, as they are too large to be eaten and have been suspected of consuming delicate plants and frog eggs.


Mites, soil nematodes, and fungus gnats find their way into every vivarium, and should not be considered pests. Detritivore mites in particular are ubiquitous, will be eaten by frogs, and are helpful to the vivarium.


When setting up a new enclosure, there are often population blooms of specific microfauna. This is a normal consequence of setting up a living system, and will diminish in due time. Conversely, keepers sometimes assume a particular species has completely died off, when it has simply found its niche and stable population density.
*Time*

Newly set up vivaria are often left to “cycle,” a term borrowed from the aquarium hobby. Strictly speaking, the new vivarium does not need to cycle the same way an aquarium would, but patience is still helpful.


Initially, a vivarium may have significant blooms of fungus in the leaf litter, soil, and hardscape components. Though a normal occurrence, it can take advantage of newly placed plant cuttings and destroy them. Allowing the fungus to die back and the microfauna to reproduce can be helpful before planting.


An initially planted vivarium may need more water and perhaps less ventilation than a lush long running system. As the plants grow larger, they add more humidity to the air. Do not be surprised if adjustments need to be made to misting and ventilation as the system ages. Similarly, be prepared to make adjustments based on seasonal differences within the household. These are reasons why designing the vivarium with easily adjustable ventilation is recommended.


Once the microfauna, fungi, plants, and climate have settled, frogs may be introduced. Thorough quarantine of newly acquired frogs is a great time for new vivarium cycling.


Author’s Note


New keepers often think first of their desires and last of the needs of the frogs. Waterfalls, ponds, carpets of moss, and constant fogging features in a small glass box are ill suited for poison dart frogs. On the opposite end of the spectrum, an artistic eye, an appreciation for design elements, and a knowledge of plant husbandry are essential to create a truly beautiful vivarium.


One could include all the elements I’ve advised against and still have an ugly display if they don’t know how to put it together, and many gifted keepers create breathtaking displays that are ideal dart frog habitats.

Contributors:

@Broseph (primary author)
@Chris S
@fishingguy12345
@Encyclia
@Socratic Monologue


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