Vivarium Construction Explained

Vivarium Construction Explained

         In this article we will discuss the main aspects of building a vivarium for Poison Dart Frogs. These aspects include the presence of a Water Feature, the construction and maintenance of the Drainage Layer, Lid Modifications, Substrate, Misting, Lighting, Background Construction, and more. The main displays at NCDartFrogs which include the “Big Viv”and the “Frog Wall” will serve as the primary examples when discussing these aspects of vivarium construction. 

The “Big Viv” at NCDartFrogs is a 48”L x 24”W x 36”H custom-built “Euro Style” vivarium. 

The “Frog Wall” at NCDartFrogs is a custom made rack system of eighteen 18”x18”x24” commercially available front-opening vivariums. 

 Will there be a Water Feature? 

     When implementing a water feature it’s design requirements must be taken into consideration from the very beginning. For the “Big Viv” the foundation of the water feature is laid out before the drainage layer was constructed. The 9”x9” pond is made with additional glass panels that are silicone-sealed in place to make sure that the pond water is kept separate from the water that collects in the drainage layer. 

Glass vivarium construction

A small pond section was put in the front right corner of the vivarium.

     Water features can pose issues in vivariums if they are not properly designed and implemented. First and foremost there is the possibility of frogs drowning. While frogs are typically associated with being great swimmers this is not the case with all types of Dart Frogs. Regardless of any individual frog’s aquatic abilities the surroundings in which the frog inhabits may need consideration. For example when female Dendrobates tinctorius reach full maturity they often become intolerant of other mature females. In a form of sexual aggression the females will often wrestle each other, and have been observed taking the opportunity to drown one another if water is present, even if just a shallow water bowl. Considerations such as this should be taken into account when deciding if a water feature is appropriate for the vivarium, and if so what type of water feature it will be. 


    The completed water feature in the “Big Viv” gives the Dart Frog inhabitants a place to deposit their tadpoles after they hatch. 

      An ill-functioning water feature not only takes up valuable land space but can also pose a potential health hazard to the Dart Frogs. Running water features tend to splash, and can create soggy conditions if the vivarium doesn’t have a well-draining substrate such as “A.B.G” (A.B.G. is a well draining substrate formulated at the Atlanta Botanical Gardens for demanding plants such as orchids). Soggy substrates and constantly wet leaf litter create ideal environments for harmful bacteria to proliferate, which could lead to skin ailments in the Dart Frogs. Some frogs in particular, such as those in the genus Phyllobates, are prone to such skin infections if not provided with dry leaf litter. 

     The water feature must be kept hygienic, as frog poop, fruit flies, and other detritus can quickly foul the water. Having a water feature that is completely removable, even if that is a simple water dish, makes keeping things hygienic easier as the item can simply be removed and scrubbed clean in a sink. 

This Oophaga histrionica “Red Head” (small form) enjoys having a water source. A half coconut shell sealed with silicone makes an easy natural-looking water dish. All of the vivariums on the “Frog Wall” have a coconut shell water dish in the front left corner. These dishes are located under the misting nozzles, whose drips after each misting cycle help ensure the water dishes stay topped-off. 

     The water in the water feature should ideally be kept separate from any water that collects in the drainage layer. The water that collects in the drainage layer will be full of heavy tannins, bacteria, and other waste that it has come in contact with throughout the vivarium.

     If the water that collects in the drainage layer is recirculated through a water feature it should be filtered first. This is most easily done with an external canister filter or filtration sump. Such filters should have Mechanical Filtration (Filter Pads or Floss) to remove suspended solids, Chemical Filtration (Activated Carbon or other Chemical Adsorbing Resins) to remove dissolved impurities, and Biological Filtration (Ceramic Media, BioBalls, etc.) to process nitrogenous wastes. Additional filtration components such as Ultraviolet Sterilization or Ozone can be used to sterilize the water of algae and pathogens.  

     Remember that water filters DO NOT remove waste from the system, rather they collect it in one location for you to ultimately remove from the system. Filters that are easy to service are more likely to be cleaned regularly, which is why external filters are more ideal than a small internal filter. Make sure that any filter, or even just a water pump, that goes inside of the vivarium be placed so that it can be easily removed and serviced. There has been successful water features that were ultimately abandoned when it’s pump stopped working and the concealment of the pump and it’s power cord prevented it from being able to be replaced without causing a great disturbance to the vivarium. 

     While water features can add a whole other dynamic to the vivarium their implementation is an advanced endeavor that should be thoroughly thought-out to ensure long-term success. 

The Drainage Layer and Lids

     Dart Frog require a very high humidity level, somewhere around 80% humidity is a good goal to aim for. It is important to note that high humidity does not mean wet. Dart Frogs are fully terrestrial animals and do not want a soggy and saturated environment. In order to maintain this high humidity the regular misting of the vivarium is required. However to prevent the substrate from becoming water-logged the substrate must rest a top a substrate barrier over a drainage layer. The drainage layer is simply an open void beneath the substrate layer that allows water to easily drain from the substrate.

Vivarium construction false bottom eggcrate window screen siliconeThis drainage layer is achieved by elevating a substrate barrier platform using horizontal PVC pipes to lift the platform about 1-1/2” off of the vivarium bottom. The platform is constructed of a cut-to-fit egg-crate/light-diffuser panel, topped with fiberglass/vinyl window screen. 

     A substrate barrier prevents substrate from falling down into the drainage layer. Vinyl/Fiberglass window screen works very well for a substrate barrier, landscape fabric can also be used although it does impede the flow of water slightly. The drainage layer can be constructed using several different methods. A method using egg crate is a superior design as it allows for relatively the greatest void volume for water to fill. It is also extremely lightweight, which can be an important consideration if the vivarium will ever have to be moved. A different but very common method to construct a drainage layer is to use stone or LECA balls. This method, while perhaps the easiest and fastest to construct, is far from the most ideal. Not only does this method add a considerable amount of weight to the vivarium, but it is also not that efficient due to the stones/LECA take up a considerable proportion of the void in which water is supposed to gather. Proponents of this method will argue that it provides a greater surface area for microfauna such as springtails and isopods to inhabit. I counter this notion by stating that most microfauna is going to be in the upper layers of substrate and the leaf litter, and larger organisms such as isopods shouldn’t be able to get past the substrate barrier and down into the drainage layer. 

Glass custom vivarium PVC egg crate drainage layerThe perimeter of the window screen is sealed and locked into position with a bead of silicone. This helps ensure some longevity to the vivarium by preventing any intrusion of substrate into the drainage layer. This will also help prevent possible clogs if the vivarium has a bulkhead installed for drainage.

  The drainage layer is basically a catchment for water that drains from the substrate after mistings. The rate at which the water collects will vary between different vivariums, with the greatest variable being how often and how much the vivarium is misted. How often and how much the vivarium is misted is dependent on a few factors. The most influential factors being the amount of air exchange the inside of the vivarium has with the ambient air in the room, as well as the climate that the vivarium is located. A vivarium in the dry hot climate of the Arizona desert is going to likely require more misting than a vivarium in a location with much greater ambient humidity such as South Florida. The degree to which this outside climate will affect the misting requirements is proportional to the amount of air exchange between inside the vivarium and outside the vivarium. The rate of this exchange will be determined by how much ventilation the vivarium has.


This 24”x18”x24” ExoTerra vivarium showing the completed Drainage Layer with sealed Substrate Barrier, as well as a modified lid. In the Mid-Atlantic down to the upper South East region of the United States a lid that is roughly 2/3 sealed glass and 1/3 open screen works well for Dart Frogs. The amount of misting can be varied seasonally to maintain the proper humidity levels. For example during winter when the home’s heating system tend to dry out the air the misting duration and/or frequency may need to be increased. 

   While commercially available front-opening vivariums typically have small vents underneath the doors on the front the largest potential for ventilation is typically going to be the lid. These commercially available vivariums typically have a fully screen lid, which in fact provides too much ventilation if they are to house Dart Frogs. Therefore these lids must be modified so that ventilation is reduced enough that high humidity can be maintained. This can be as simple as laying a sheet of glass on top of the metal screen. However a more professional and longer lasting lid can be made by removing all the metal screen from the frame of the lid and replacing it with a strip of rust-proof fiberglass screen and siliconing in a pane of glass. These vivariums come with a rather course metal screen, this is needed for some reptiles that eat larger prey items such as roaches and super worms which can chew through fiberglass screen. However this metal screening, even if it is (low grade) stainless steel will rust over time, especially if glass is laid directly on top of it which holds moisture on the screen constantly. The mesh of the stock screen may also be large enough to allow fruit flies to pass through. For both of these reasons fiberglass window screen, especially that which has fine mesh to prevent small bugs from passing, is a preferred material.
   
  A modified lid on an 18” cube ExoTerra vivarium. Notice the front vents running the length of the vivarium located directly below the doors. 

   More serious hobbyists looking for a clean and custom look often build “Euro Style” vivariums to fit their exact space requirements. These vivariums are custom made, so if done correctly no retrofitting is needed. These “Euro Style” vivariums have a horizontal “step-vent” beneath sliding front doors, as well as a strip of screen on the top running the length of the vivarium. The “Big Viv” at NCDartFrogs is such a vivarium. 

     Both commercially available front opening vivariums as well as the custom made vivariums have ventilation below the front doors and well as on the lid. This is not random, but rather a purposeful design feature that helps to keep the front viewing panels clear of condensation by guided passive ventilation. When the lights on the vivarium are on they slightly warm the air inside of the vivarium. As this warmer air rises it leaves the vivarium through the top vent and is replaced by outside fresh air entering the vivarium via the lower front vents beneath the doors, and the cycle continues. This creates a passive flow of air over the front viewing panels which decreases the amount of condensation that builds on the viewing panels.  

     The absence of passive ventilation over the viewing panel is one of the major disadvantages of using a top-opening aquarium as a vivarium. The relatively stagnant ventilation conditions of an aquarium used to make a vivarium can also affect other things such as plants. Some plants, such as orchids, need some amount of air flow to maintain health. The strategic use of small circulation fans can help mitigate these shortcomings. 

      Depending on the balance between the frequency and duration of misting with the amount of evaporation and transpiration taking place the drainage layer may fill with water over time. The amount of water in the drainage layer is not important, as long as it doesn’t rise high enough to reach the substrate. When the drainage water level reaches the substrate it can be wicked back up into the substrate. This completely negates the effectiveness of the drainage layer, and necessitates that the water level be lowered.

     With foresight and planning ahead of time this can be a simple process. The most convenient situation is to have a drain installed before you start on the drainage layer. This requires drilling a hole in the glass, either on the bottom or very low on one of the sides. This will allow the draining of excess water on a continuous basis without any interference from you. For those people who are hesitant to drill glass there are still design methods that can be implemented during the vivariums construction to make draining the drainage layer easier, although the water level in the drainage layer will still need to be checked regularly, and lowering the water level done manually. Such methods are basically a design feature that allows easy access to the drainage layer. For example a short length of 1” diameter PVC pipe that passes through the leaf litter, substrate, and substrate barrier that opens up in the drainage layer. This short section of pipe acts as a port hole or well. A small hose can then be passed through this portal and down into the drainage layer water, allowing it to be siphoned out and the drainage layer emptied. A plug or cap should be used to close this passage way when not in use so that any adventurous frogs do not go spelunking. A piece of cork or wood can be used to disguise the port. 

A drain installed below the substrate barrier will automatically prevent the water level in the drainage layer from rising to the point at which it comes into contact with the substrate. 


Large numbers of vivariums are more easily maintained when regular maintenance requirements are automated. The drainage plumbing on these vivariums is constructed using 3/8” O.D. tubing and 3/8” Push-Connect fittings. The holes were drilled in the glass using 22mm diamond hole-saw bits. The gaskets for the bulkheads are 3/4” garden hose washers. When designing larger drainage systems make sure to consider fluid dynamics and include necessary features such as those found in household plumbing systems. For example air intake vents to prevent gulping and possible air-locks. Also if the vivariums are to be drained directly outside include a P-trap to prevent outside air/insects from traveling into the vivariums. 

Misting

    In order to maintain a high level of humidity around 80% that Dart Frogs require the vivarium will have to be misted. This can be done manually using a spray bottle or a pump mister, or it can be done with an automated misting system.

     Whether hand misting or using a misting system you will want to make sure to use appropriate water. In addition to the requirement that the water be free of chlorine and chloramines ideally the water has a very low mineral content to help prevent hard water spots from forming on the glass. Purified water such as Reverse Osmosis or Distilled water is perfect for use as misting water. “Spring” water and other drinking water that has minerals reintroduced after the purification process “for taste” are safe to use, but may leave spots on the glass. 

      The amount of misting a vivarium will require depends on several factors which were discussed earlier in this article. The goal is to maintain a relatively constant higher humidity level of around 80%. Lower humidity levels around 50-60% can be tolerated, at least briefly, especially if a water source is provided. 

     Installing a misting system is one of the most basic ways to help ensure that your vivarium will be successful. An automated misting system frees you from having to manually mist the vivarium on a regular basis. This can be especially beneficial for people that live busy lives with work and small children, or people that like to go away on weekends. 

     While hand misting once or twice daily will produce relatively large swings in humidity between mistings, using the timer of an automated misting system allows the daily misting allotment to be broken down and spread throughout the day to provide more even humidity levels. For example the system could be programmed to mist for 5 seconds every 3 hours while the lights are on. Misting should not take place immediately before the lights turn off, or during the night, to prevent water from standing on the plant leaves for long durations which could lead to fungal problems. 

     The misting schedule will vary based on the vivariums distinct factors, with the goal of maintaining around 80% humidity. This target range can be measured with a humidistat placed inside of the vivarium. Unfortunately most of these devices do not last long, especially in very high humidity environments, and tend to become inaccurate rather quickly. This is especially true of units that are kept inside the vivarium for continuous monitoring. Therefore it is important to learn to judge humidity by the appearance of the vivarium. This is a skill that is learned through observational experience. For example the vigor and plumpness of plant leaves or the presence of condensation on the glass close to and beneath the substrate and leaf litter can be used as gauges of humidity. Being able to get the misting scheduale dialed in correctly is one of the reasons it is recommended not to immediately add frogs to a freshly made vivarium. Give some time for the vivarium to establish itself and allow yourself the opportunity to make sure all the parameters are in line. 

     There are several different misting systems on the market, and you tend to get what you pay for in regards to the units reliability and longevity. Mist King brand misting units made by Jungle Hobbies are the industry standard when it comes to quality. There are not many pieces of technical equipment that are needed for a vivarium, and of those a misting system is at the top of the list of equipment that should be invested in.

 

The Mist King systems at NCDartFrogs do not drawl water from a reservoir, but rather are fed directly from the pressure tank of the Reverse Osmosis system. This method requires the use of a solenoid valve that closes when the pump is not running to prevent the pressure tank from making the misting nozzles drip. Such a design, along with the vivariums having drains that empty outside, results in a hydrological cycle that is completely automated and hands-off. No manual misting, filling of misting reservoirs, or emptying of drainage catchments! 

Substrate

Vivarium soil drainage layer

A layer of Aquatic Soil designed for use with freshwater planted aquariums was used a a first substrate layer. The decision to do this was the result of several considerations including providing a source of various elements and minerals into the closed ecosystem that would develop with the plants and microfauna. This was topped with the primary substrate of ABG. 

    There are several materials and methods that can be used as a substrate for a Dart Frog vivarium. The industry standard is the use of “ABG”. “ABG” is a substrate mixture developed by the Atlanta Botanical Gardens that consists of tree fern fiber, milled sphagnum moss, milled peat, horticultural charcoal, and orchid bark. This is a course mixture that drains well and allows for oxygen to permeate into the soil to prevent anaerobic or even anoxic conditions from forming. These conditions are ideal for frog health and plant growth in the vivarium. Slight adjustments can be made to this substrate mix if desired or if some ingredients are not obtainable as long as it doesn’t change the attributes that make ABG so ideal. 

     There are other methods that can be used instead of ABG that are also suitable for a Dart Frog vivarium. Turface is a fired calcine clay product (commonly used on baseball fields) that has been successfully used in place of ABG. Filter foam is another method that has also been used successfully in Dart Frog vivariums, replacing not only the substrate but also acting as the drainage layer, with plants rooting directly into the foam. 

   While there are several acceptable alternatives to ABG, there are also several methods that simply will not be successful long term. One commonly seen example is the use of coco coir, which comes as a compressed brick commonly found in the reptile section of big box pet stores. Coco coir simply holds too much moisture and does not drain adequately. This results in the substrate quickly becoming a dense saturated sponge for bacterial growth that inhibits plant growth and can lead to health issues for the frogs. 

    Whatever substrate is used there should always be a nice layer of leaf litter on top. Leaf litter is added in after planting the vivarium, applied like mulch is in a garden, so that no substrate is exposed. The leaf litter serves several purposes. To begin with the leaf litter covers the substrate so that it does not stick to the frog’s moist skin, which can becoming irritating and stressful to them (in fact healthy Dart Frogs shed their entire skin almost every morning in order to keep this vital organ nice and clean!). The leaf litter also serves as endless shelter for the frogs. Being able to dart into cover gives the frogs a sense of security and is good for their wellbeing. Leaf litter also supports the cleanup crew of the vivarium which includes springtails and dwarf isopods. 

Background and Hardscape

     Although they are not absolutely necessary the use of a background in the vivarium can make the vivarium more visually appealing, as well provide more usable surface area for the frogs to live on. There are several different methods that can be used to construct the background of the vivarium. Two of the most common methods are the Carved Foam Method and the Cork Mosaic Method.

     The Carved Foam Method uses sheet or spray foam that is attached to the back panel of the vivarium with silicone. The foam is then carved and shaped, after which it is sealed. There are two main techniques used to seal the foam, each of which produces a much different finished look.

     The first technique with foam backgrounds is to cover the foam with 100% Silicone, using gloves to smear and completely cover the foam. After covering the carved foam with silicone a substrate material such as ABG, coco coir, crushed tree fern panels, or other material is poured over the entire background where it adheres to the silicone. The material can be slightly pressed into the silicone to ensure a good bond. After allowing the silicone to dry any excess material is brushed or blown off the background. This process may take more than one application to ensure complete coverage. 

     The second technique with foam backgrounds is to paint several layers of Drylok onto the foam. Drylok is a cement/grout mix, that can be tinted different colors, and with practice and artistry can give the appearance of rock or wood.

     The Cork Mosaic Background is the preferred method used at NCDartFrogs, and provides the most natural appearance. With this method pieces of cork (as well as any other hardscape materials such as wood branches) are siliconed onto the back panel of the vivarium. After the silicone dries and the items are secured into place more silicone is applied into all the gaps and cracks between the pieces of cork. Hydrated sphagnum moss is stuffed into these gaps and cracks, completely filling the background. In addition to the cork and moss surface providing a great surface for plants to grow upon, the root bunches of many different small plants can be tucked into the many crevices in the background, producing a stunning background. 

Vivariums laid on their back during background construction.

The various pieces of cork and wood can be laid out and manipulated when first designing the background. Then once a desirable background is reached the pieces can then have silicone applied to them and be set into place. 

Cork Mosaic Background method with cork bark, silicone, sphagnum moss.

Siliconing the cork to the background is most easily done with the vivarium laying on it’s back (before the substrate is added). When this is not feasible, such as in the case of NCDartFrog’s “Big Viv”, supports may be needed to hold pieces in place until the silicone dries. 

 

This is a finished background and hardscape using the Cork Mosaic Method. Not only does this background immediately increase the usable surface area of the habitat for the frogs, but it also encourages vining and shingling plants to grow upon it, and allows epiphytic plants such as bromeliads to be planted on it. This allows the frogs to exploit the full vertical potential of their vivarium, creating a much more dynamic environment.

Lighting

     Although Dart Frogs do not require basking lights and heat lamps like many reptiles they are diurnal visual predators, requiring some light in order to hunt their prey. In addition to this Dart Frogs do best when housed in an environment with live plants, and for the live plants to thrive they need adequate light intensity.

     There are many lights that can provide the intensity needed, but not all are suited for Dart Frogs. For example Metal Halides or High Pressure Sodium bulbs can provide intensity needed for lush plant growth, however they also project a lot of heat down into the vivarium which can quickly desiccate Dart Frogs. More efficient lights that produce more light and less heat by-product are therefore needed for Dart Frog Vivariums. While fluorescent lights, such as high-output T5 bulbs, can be used with stunning results the latest technologies in LED lighting make them ideal for use in vivariums. LEDs are able to produce intense light, while having a heat sink that drawls heat away from the LEDs. On larger fixtures the light may employ fans along with the heat sink to direct heat up and away from the light. LEDs also have the benefit of operating for many years before they need replacement, whereas florescent bulbs should be replaced yearly to prevent spectrum shift. 

     There are many LEDs on the market that are suitable from use over vivariums. On one end there are inexpensive general-purpose LED strip lights. These lights are not adjustable at all, so you will want to choose one with the right specs. A light with a color temperature of 5000°K to 6500°K will provide the bright and crisp light similar to natural sunlight. These LED strip lights are not that intense, often just using aluminum housing to dissipate heat. These strip lights may need to be doubled up to get the intensity desired.
     
      Going from here, increasing in price as well as features, are lights that may include a built-in timer as well as control over the intensity of the light. Many of the lights made for Freshwater Planted Aquariums would fit in this category. These lights are great for use on vivariums as well.

      On the high-end of the lighting options are lights that offer many features. For example not only do they have a built-in timer that simply turn the lights on and off, but they often have ramp-timers that increase and then decrease the light intensity over the course of the photoperiod. While intermediate lights allow you to control the intensity of the light, the high-end lights allows you to also change the spectrum of the light. For example starting out with a cooler blue light at dusk, increasing to a warmer full spectrum intensity during the peak of daylight, then decreasing down again finishing off with a reddish sunset. These top-tier lights are often controlled by an app on your phone. Some of these lights have such extravagant features as being able to mimic lightening storms, mimic the changing photoperiods throughout the year, or even mimic the lighting aspects provided by the sun in tropical locations over the globe. Many of these high-end lights have their origins in the reef aquarium industry, in which lighting plays a major role. 

      There is no one light that would be the best option for all vivariums, as the needs of individual vivariums vary. For example the “Big Viv” at NCDartFrogs is 36” in height and required LEDs with optical lenses to focus light all the way down to the bottom. High light intensity was also desired to be able to keep the bright red and pink colors of the bromeliads, which would otherwise “green-out” under lower intensity lighting. It should be mentioned that light intensity over vivariums is not simply “the more the better”. Not only is it possible to “sunburn” plants but also too great of a light intensity could cause frogs to remain hidden in the plants and reluctant to come out. 

     Thanks for taking the time to read this article, I hope it provides some guidance. As a special offer use code “BLOG2” to get 20% off your next frog or tadpole purchase at NCDartFrogs.com 

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