Amphibian Care >> Tropical Terrarium Design

Introduction: Keeping reptiles and amphibians in living terrariums has rapidly increased in popularity over the last decade. A cage that combines live plants and animals together looks attractive and may be beneficial for certain species. Many people who haven't kept animals in a terrarium often avoid them because they assume that they are difficult to create or keep clean. When properly planned and cared for, nothing could be further from the truth. Although terrariums take time and planning to setup, they are by no means difficult to make. The key to long term success is careful planning during the beginning and keeping up with regular maintenance, such as spot cleaning and pruning plants.

Unfortunately, not all reptiles and amphibians can be kept in terrariums or vivariums because of their size, amount of waste produced, or behavior, and it’s important to identify if the species being kept will tolerate a terrarium prior to making one. Avoid most large species of reptiles or amphibians because they often trample plants and are messy. Species that burrow or dig are also poor candidates for a tropical terrarium because they often uproot plants. Herbivores should be avoided for obvious reasons.

The Enclosure: Tropical terrariums are moist, and it’s important that the bottom portion of the cage is waterproof so that excess water does not leak out. Standard glass or acrylic aquariums work well and are widely available. Specialty reptile tanks with sliding or hinged front doors also are a good choice. They work particularly well for terrariums that house skittish animals which may be frightened by a hand entering from above like with a standard glass aquarium. Realize that the size of the cage that is used will limit what types of plants are used and what features can be included inside the terrarium. Larger enclosures are preferred, because they provide you with more options.

The type of cover or lid that is used depends on the needs of the reptile or amphibian that is being housed in the tank. Screen covers can be purchased from most pet stores and provide excellent ventilation. They can be modified by taping plastic wrap or glass over part, which will help maintain high levels of humidity. Glass can be cut for a cover at glass shops and some tropical fish stores. Ventilation can be provided by either having small holes drilled in the glass or by cutting out a large hole and covering it with aluminum window screen. Good air circulation is important for most herps and many common plants.

When planning the cover, make sure that it accommodates the types of lighting that are required for the animal in the terrarium. UVB rays are important for most diurnal reptiles. They will be filtered out through glass and fine screening so light bulbs that produce UVB radiation need to be placed over a screen section of the cage. Basking and spot lamps often crack glass and melt plastic.

Background: The type of background that is used can have a large effect on the aesthetics of a terrarium. Simple black paper or poster board can be taped to the outside of the tank. This works well for small terrariums with terrestrial animals. In many situations, it’s beneficial to attach an actual background to the inside of the terrarium that plants can grow on. This creates a whole new dimension to the terrarium and works great for tall tanks. It’s easiest and often required to attach the background to the cage before putting anything inside. There are many different backgrounds available. Most can be attached to glass with aquarium-safe silicone sealant, which can be purchased from pet stores or hardware stores. Below is a short list, description, and review of background that are commonly used:

Cork Bark – Cork bark forms an attractive background to which epiphytic plants can be attached. Bark flats are sold at many pet stores. One of the best qualities of cork bark is that it is waterproof and last a long time in moist conditions. Natural cork bark flats are usually curved to some degree and leave a small gap between the middle of each piece of bark and the glass. This empty space should be filled with soil or gravel to prevent animals in the cage from becoming trapped between the glass and the bark. Alternatively, pressed cork bark panels can be purchased from specialty terrarium supply companies which are completely flat and won’t leave a gap between the glass and the bark.

Tree Fern Panels – Tree fern panels are made from the roots of certain tropical ferns. These panels are dark black to chocolate brown. Tree fern panels look great and work well for mounting epiphytic plants. Unfortunately, they are rarely harvested from the wild in a sustainable way. A better alternative may be found in a product called EpiWeb, which resembles tree fern panels but is made from recycled products.

Coconut Fiber Panels and Sheets – Coconut fiber panels are made from the long fibers that look like hair and grow on coconuts. They are readily available at garden centers as well as from terrarium supply companies.Coconut fiber is inexpensive and practical.

Coco Panels – Vivaria Projects in the Netherlands makes a wonderful product called coco panels. They are made from coconut husk fiber that is pressed together with some sort of adhesive. Plants are easily attached to coco panels with wiring. They can be ordered in the United States from a few select terrarium supply companies.

DIY Backgrounds – Rather than purchase a background and glue it to the back of the terrarium, many people prefer to make their own. There are dozens of techniques and styles. One of the most common methods is to use a spray-on polyurethane insulation foam, such as Great Stuff - Gaps and Cracks. This can be sprayed onto the back of the cage and layered to great a unique shape and texture. This foam is then followed most often by black or bronze silicone sealant in order to make it waterproof and safe. Directly after the silicone sealant or other waterproof sealant is applied, dry coconut husk fiber or peat moss is pressed into it to give the background a natural appearance. A similar method for creating a terrarium background is to use styrofoam insulation sheets. These large sheets are cut and shaped using a foam cutter, covered with silicone sealant and coconut husk fiber or peat moss as mentioned above, and then attached to the back of the cage. There are many other techniques for creating a background in a terrarium, the abovementioned two are only common ones. It may be helpful to search online or visit some of the links at the bottom of this article to find out more about other styles of backgrounds.

1) Foam background coated in peat moss, bark, and gravel 2) Coco panels 3) Cork bark with moss

Substrate: Tropical terrariums will last longer if a drainage area is created below the soil or bedding so that extra water can drain through the soil into a reservoir. Without this drainage area most soils become waterlogged quickly and will need to be changed often, disturbing the biological cycles that occur within. The drainage area can be created a number of ways. Gravel is cheap and can be purchased at almost all pet stores. Using 2 or 3 inches (5 cm to 7.5 cm) of medium to large gravel beneath the soil is an easy way to create a drainage area. Unfortunately, gravel isn’t practical to use in all situations because it is heavy. In large terrariums it’s generally best to use a lighter substrate beneath the soil. LECA (lightweight expanded clay aggregate) is an excellent substitution for gravel. It can be purchased through some garden centers and hydroponics supply stores in the United States under the brand name Hydroton. A false bottom is also a good way to provide a lightweight drainage area. Over the drainage area a layer of fiberglass window screening can be placed so that the soil does not slowly fall below into the water.

There are dozens of recommended terrarium soil mixtures online and in books. Many successful soil mixtures used in tropical terrariums are based off of coconut husk fiber. This product is made from coconut shells that have been ground into a soil and then compressed into a dry brick. When placed in water, this brick expands back into a moist soil-like media. Common brand names that it is sold under include Bed-a-beast, Eco Earth, Forest Bed, Coco Peat, and Eco Peat. Coconut husk fiber decomposes very slowly, has a neutral pH, is made from a renewable resource, and is cheap. It can form the majority of the substrate used in a tropical terrarium.

In the past I’ve used peat moss in place of coconut husk fiber, but the more that I learn about peat moss the more I hesitate to use it. Peat moss takes hundreds of years to form and currently is mostly collected in an unsustainable way by basically destroying and digging up bogs. In the terrarium, it decomposes quickly and needs to be changed often. It also is slightly acidic which can be harmful to certain terrestrial amphibians. The one practical application that I’ve found for it is when it’s used to grow live moss or carnivorous plants. Most types of live moss and carnivorous plants grow best on a soil that is slightly acidic and peat moss works well in these situations, but is best mixed with other ingredients.

In with coconut husk fiber, it's advantageous to mix in other materials. Orchid bark, fir bark, or coconut husk chunks can be mixed in to provide better drainage. Orchid bark can make up the majority of the soil in areas where plants that do best in well-drained soil are used, such as bromeliads. Sand, tree fern fiber, shredded oak leaves and leaf compost, milled sphagnum moss, activated carbon, and chopped live moss can also be added. I almost always add a small amount of leaf compost to terrarium soil mixtures. This usually introduces beneficial micro-organisms that help to maintain the terrarium. Occasionally leaf compost will also introduce pests, such as snails or slugs, and potentially could introduce harmful pathogens to a terrarium, so take this into consideration before using it. Milled sphagnum moss can be mixed in to provide extra nutrients for plants and to help breakup and aerate the soil. Activated carbon is used in aquariums to remove organic waste. It serves the same purpose in terrariums, but essentially is used up after a few months and needs to be changed.

Drainage substrate layers. Left to right: 1) False-bottom 2) Gravel 3) Hydroton clay pellets

Furnishings: There are many different items that can be used to furnish a terrarium. They may serve a purpose (such as a basking site for small lizards or shelter for nocturnal frogs), or may simply add aesthetics.

Cork bark slabs can be used to hold soil back in certain areas, creating small hills and cliffs. Cork bark tubes can be planted with epiphytic plants to make them look like over grown fallen logs. Driftwood can be purchased at many pet stores, and can be used as a centerpiece for the terrarium. River rocks and slate can be used as cage decor and add a nice touch when they are placed along side of a water area. Generally, terrariums look best when only one type of wood is used. Too many different types clutter the terrarium and make it look unnatural. Wash all wood or rocks with hot water before placing them in the terrarium.

Before using a piece of wood or rock consider the care requirements of the reptile or amphibian you plan to keep. Does the animal need a basking spot? Arboreal or terrestrial hiding spots or egg-laying sites? How about a few hiding areas? Wood and rocks can be attached to higher areas in the terrarium with silicone sealant to create a dramatic effect. Ensure that all rocks and wood are stable and will not be knocked over by the reptiles or amphibians being kept.

Lighting: The type and amount of lights to use depend on the plants and animals being kept. In small terrariums that have a few low light-tolerant plants in them, and an animal that does not need any special type of lighting, a single fluorescent tube can be used. Tall terrariums with plants that like bright lighting may need more. Multiple standard T8 or T12 fluorescent bulbs can be used, but better options can be found in power compact fluorescent lighting. For particularly large enclosures, metal halides can be used.

The color temperature or Kelvin rating of the bulbs used has a large impact on the appearance of the terrarium. Bulbs with a low color temperature below 5000K often give a yellow or red hue to the terrarium. Those with a high color temperature above 6500K produce a purple or blue tone. Different people favor different terrarium appearances, but I generally prefer using bulbs with a color temperature near 5500K or 6500K. These bulbs are often referred to as “natural white” or “daylight” bulbs because they produce a bright white light similar to the color temperature of the sun during midday. Multiple bulbs are not always needed, but will help increase plant growth and generally improve the appearance of most terrariums. In addition to color temperature, the CRI (color-rating index) rating of a bulb is also important to look at. This rating determines how the colors of plants and animals in the terrarium will appear. The sun has a CRI rating of 100, so when choosing a bulb try to locate one with a high CRI rating, preferably above 80.

The animals in the terrarium may require additional lighting to the types mentioned above. Most diurnal lizards and turtles need a light bulb that produces UVB radiation in order to process calcium from their diet. Both fluorescent and power compact bulbs are available from pet store that produce UVB radiation. Many species of lizards and some species of arboreal amphibians will also appreciate a basking spot in the cage that is produced by using an incandescent light bulb. It’s important to usw an accurate thermometer to check the temperature of this basking spot to ensure it does not get too hot.

Plants: Live plants make terrariums what they are. They add a dimension of life and color that can’t be replicated with artificial plants. Different types of plants require different environments to live in just like animals, and not all species grow well in a tropical setting. High humidity and moist soil will cause many species to rot or mold. These conditions also cause many plants to grow too quickly, or get too large too fast which makes them unsuitable to use. It's advantageous to seek out dwarf plant varieties from specialty terrarium supply companies.

Epiphytic plants can be grown on backgrounds or pieces of wood in the cage to create an arboreal area for small animals to climb. Ground covers and low growing plants can transform the soil into a green living carpet. Tall broad-leaved plants can be used as center pieces in the terrarium, and plants with small leaves can be used to accent them. Below is a list of some commonly available plants that I have used successfully in a tropical terrarium, clicking on the scientific name of most will display a photograph of the plant.

Scientific Name	Common Name	Comments
Aglaonema modestum	Chinese Evergreen	-
Alocasia species	Elephant Ear	For tall terrariums only
Cissus discolor	-	-
Crypthanthus species	Earth Stars	Needs well-drained soil
Dieffenbachia	Dumbcane
Ficus pumila	Creeping Fig	Fast growing vine, great for backgrounds
Fittonia species	Poke-a-dot Plant	-
Geogenanthus undatus	-	-
Guzmania species	Bromeliad	-
Humata tyermanii	Rabbit's foot fern	Can grow large
Marantha tricolor	Prayer Plant	-
Neoregilia species	Bromeliad	Many miniature species that are great for small terrariums
Pellaea rotundifolia	Button Fern	-
Pellionia pulchra	-	-
Peperomia fraseri	-	-
Peperomia meridana	-	-
Peperomia obtusifolia	Baby rubber plant	Grows quickly, very hardy
Pilia species	Aluminum plants	Grow very quickly
Philodendron species	Philodendron
Polypodium polycarpon 'Grandiceps'	Cobra Fern	Epiphyte
Polypodium polypodioides	Ressurection Fern	Epiphyte that needs high humidity
Saintpaulia species	African Violets
Scindapsus aureus	Pothos, Devil's Ivy	Another classic, grows well in a wide range of conditions
Scindapsus pictus	Silver Vine	Does best in well-drained soil
Selaginella species	Club Moss, Golden Club Moss	Great ground cover, requires high humidity
Syngonium podophyllum	Arrowhead Vine	Very hardy, may quickly outgrow a terrarium
Tillandsia cyanea	-	-
Tradescantia fluminensis	Wandering Jew	Good for backgrounds or a ground cover
Vesicularia dubyan	Java Moss	An aquatic plant that can be grown on land when kept moist
Vriesea species	Bromeliad	-

Plants that are purchased at local garden centers or hardware stores should be washed with water before being placed in the terrarium. Many stores use fertilizers, pesticides, leaf shiners and other chemicals on their plants that could be harmful to reptiles and amphibians. Purchasing plants through the mail from specialty terrarium supply stores is usually the safest route to go.

Moss: Many people desire a lush green carpet of moss to grow in their terrarium. While it is certainly possible to successfully grow moss, not all types of suitable for use. Avoid species from temperature climates, which may need a dormant period in winter and often only last a year or so in the terrarium. Tropical mosses can be purchased from terrarium supply companies that are better, but still can be tricky to grow. There are also ethical concerns about using commercially harvested moss in a terrarium.

Rather than purchase moss for use, most terrariums will develop moss on their own given time and this is the preferred way to grow moss in a terrarium. You can also use hardy plants that resemble moss as an alternative. Java moss (Vesicularia dubyan) is a superb option. It's an aquatic plant sold at many tropical fish stores, but when draped over a moist land area or log emerging from the water it also grows well.