The Aussie Comprehensive Care Guide:
Green Tree Monitors (Varanus prasinus)

The Green Tree Monitor (Varanus prasinus) represents a true pinnacle of the reptile keeping hobby. Breathtakingly vibrant, intensely active, and remarkably intelligent, these small predators offer an unparalleled experience for the dedicated enthusiast.

Green tree monitors are highly sought-after and rare within the Australian hobby. Due to licensing restrictions, they can only be kept in a few states, with Queensland being home to the majority of breeders. Please note that this guide reflects my personal husbandry practices and what has worked successfully for my own collection.

In my experience, the care requirements for hatchlings and juveniles differ significantly from those of adults. For example, mature monitors can safely process much heavier, higher-protein meals than younger animals.

To make this information easy to follow, I have divided this guide into life-stage sections, focusing primarily on the two most important shifts in their care: diet and enclosure size.

Quick Facts

Fralon Breeding Behaviour - Sheet2 (3)_e

CURRENT GOING PRICE IN AUSTRALIA (2026)- $5000-$6000 AUD Each for Hatchlings

Adults are hard to come by and are often priced around $9000-$10,000 AUD Each

Please note: This species is arguably one of the most difficult Australian species to breed. Getting the nesting conditions exactly right is highly challenging, which makes producing viable eggs incredibly hard. This is ultimately why there are so few successful breeders across all of Australia.

Stage 1: Hatchling (0-1 Year old)

When acquiring a Green Tree Monitor (GTM), the animal should be a minimum of two months old. It is imperative to consult directly with the breeder to determine exactly what the animal is currently feeding on so you can replicate that diet during the transition.

Upon arrival, your GTM will likely be transported in a secure container and will need to be carefully transferred into its new enclosure. It is important to understand that GTMs are an exceptionally shy and nervous species, even by monitor standards. As a result, you should anticipate a significant acclimation period; it is entirely normal if you do not see your new monitor for the first week or two while it settles into its environment.

Once the animal has acclimated, if your goal is to build a foundation of trust and safely handle your GTM, I recommend referencing my Monitor Lizard Socialization Encyclopaedia for a comprehensive, step-by-step approach to building that relationship.

Click here for the Monitor Socialisation Guide!

Step 1- Enclosure Size & Design

When setting up a GTM hatchling enclosure, simple is best!

ENCLOSURE SIZE:
For a hatchling you want either a 2ft W x 2ft D x 3ft T OR 3ft W x 2ft D x 2ft T.

ENCLOSURE MATERIAL:

There are 3 main different enclosure materials, Glass, Melamine & PVC.

While glass enclosures often receive mixed reviews, much of the criticism comes from keepers in colder, drier climates who naturally struggle to maintain heat and moisture. In my experience, glass terrariums (like Reptile One models) work exceptionally well for raising babies as long as your room's ambient humidity is already sitting around 50–60%. If you live in a drier area, you can easily adapt a glass setup by covering half of the mesh roof with a sheet of acrylic or plastic to trap the humidity.

With that said, PVC enclosures are widely considered the gold standard on the market due to their superior insulation and moisture resistance. Melamine enclosures are another option that retain heat very well, but they require careful maintenance as they are highly susceptible to water damage over time.

IMPORTANT NOTE: I highly recommend choosing swing-open doors over sliding doors. Depending on the size of your hatchling, they can sometimes squeeze right through the small gap between two sliding glass panels. For this reason, I prefer glass and PVC enclosures, as they frequently come with swing-door options.

Reptile One Enclosure Range

Exo Terra Enclosure Range

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Habitats at Home PVC Enclosures

ENCLOSURE FURNISHINGS:

This species are tree dwellers, so you will need to furnish the enclosure with plenty of branches.

I also highly recommend installing a 3D background to maximize their climbing space. Great options include fake rock (which we will cover in more detail soon), bark slabs, cork panels, or any other climbable material. Let's break down the pros and cons of each:

Fake Rock Background:

In Australia, the go-to material for DIY fake rock backgrounds is Tile Pointing. It dries to a water-resistant, sandy texture and is conveniently available in pre-mixed buckets of various colors. While you can use grout or concrete, I’ve found them to be very inflexible unless you use expensive additives.

When researching online, you might see warnings about fake rock backgrounds "grinding their nails down to the beds." This concern largely comes from keepers in the US who use a different product called Drylok, which has a much rougher texture. I have kept my tree monitors with a DIY Tile Pointing background for the last two years and haven't had a single issue with their nails wearing down.

To soften the background's texture slightly, I apply a layer of outdoor paint—which I do anyway to give the wall a natural, multi-colored rock look. Finally, I lock everything in with a concrete sealer, which has worked wonders.

If you are interested in a step-by-step guide on how I build my 3D backgrounds, click the button below.

Bark slabs:

Bark slabs or bark fencing are another popular background option for all kinds of monitors in Australia. They look fantastic and provide a highly natural climbing surface for Green Tree Monitors (GTMs). I have used them in various setups, securing them to the back and sides of the enclosure in a couple of different ways:

1. Screwing them in: This method is quick and easy. However, over time the bark can shift or break, which can leave an exposed screw head that could easily injure your GTM.

2. Liquid Nails: This method is a bit more time-consuming, and I highly recommend applying it in a well-ventilated room away from your animals. It requires a long drying time—I usually let it cure for a full 24 hours just to be safe. That said, I've found this to be the superior method. I haven't had much fall off once secured. Since natural bark is rarely perfectly flat, Liquid Nails is excellent because you can use extra adhesive to fill the empty voids behind the wood. If you end up with any visible gaps, you can simply add more Liquid Nails and press in a small piece of bark for a seamless finish. Overall, it works much better than screws.

Cork Panels:

Cork panels are fantastic. Because they are typically quite wide, they tend to be much easier and less time-consuming to install. However, in Australia, cork is expensive and can be hard to come by. If you do manage to find some, they are definitely a great option. You can attach them using the exact same methods outlined in the bark slab section.

Coir Rolls/Panels:

For my first GTM hatchling enclosure, I used this material. It was cheap and easy to cut to size, but you have to make sure you use the right adhesive to secure it. This is where Liquid Nails shines again. You will need to work on each side separately, using heavy items to weigh the coir background down into the adhesive to ensure a strong hold. You DO NOT want any gaps, as feeder insects and even the monitors themselves can weasel their way behind it.

BRANCHES:

Now that you have chosen your enclosure and background, it's time to select the branches. Since these are tree monitors, we essentially need to bring the trees indoors.

How you mount the branches will depend on your enclosure material. With PVC and melamine, you can screw the branches directly into the walls. With glass, you cannot do this; instead, you will need to secure them using silicone, expanding foam, or by carefully wedging and leaning them against the walls (ensuring they absolutely will not fall).

I use branches collected from a friend's property, but aquarium driftwood works well too. Whatever branches you find, give them a thorough hose down and a soak in hot water as an extra precaution. Crucially, make sure any branches you use are completely dead and not from a live tree, as fresh sap can harm the monitors.

When it comes to branch thickness, there is no strict rule—you just want a good variety. The only branch where thickness really matters is the basking spot. This branch needs to be fairly wide; it should be thick enough that when the monitor flattens or "pancakes" out, its stomach doesn't spill over the edges. This ensures they absorb heat evenly and prevents hot spots on their body.

When you are positioning the layout, ALWAYS position the basking branch first. Then, add the remaining branches around it using a combination of vertical and horizontal angles. The basking branch itself should be horizontal—it doesn't need to be perfectly flat, but you definitely don't want it on a steep angle.

How densely you pack the enclosure will depend heavily on your socialization goals. Just keep in mind that the more densely packed the enclosure is, the harder it becomes to clean, feed, and change the water. I have also found that leaving strategic gaps between the branches encourages them to jump. This is a natural behavior and is incredibly cool to watch!

Below is a very basic enclosure design with Horizontal branches, and coir panel background. This worked well for young GTMs. The dirt was added in later, unfortunately I did not take a photo.

Fake Plants/Foliage:

You can use either live or artificial plants in your enclosure, but for your first Green Tree Monitor, I highly recommend sticking to fake plants. You can easily find them at hardware stores, pet shops, or online.

That being said, I wouldn't recommend over-cluttering the space with too much foliage. Remember that the more densely you pack the enclosure, the more hiding opportunities the lizard has, which means they won't be out and visible as much. This is a crucial point, especially for skittish lizards—if you give them too many places to completely disappear, they absolutely will!

WATER BOWLS:

Now that your branches are in place, the next step is adding the water bowls. There are two different styles you can use for your GTM:

2. Standard Ground Water Bowl: You can absolutely use a standard water bowl on the floor of the enclosure. Simple plastic bowls or naturalistic resin ones both work well. As mentioned above, providing both an arboreal and a terrestrial option at the same time is a great approach.

Key Note: Tree monitors often prefer drinking moving water, such as droplets from a hand sprayer or an automated misting system. However, you must ALWAYS offer a standing water bowl to ensure they have constant access to hydration.

1. Arboreal Water Bowl: Arboreal water bowls (like the one pictured to the right) often consist of a 3D-printed frame that holds a removable plastic container. Depending on your enclosure's material, you can screw the frame directly into the walls or attach it to the wood. I screwed mine right into the main log. You can definitely provide multiple water bowls, but the key is to ensure the monitor can easily reach them. For instance, if you haven't installed a climbable 3D background on the sides of your enclosure, avoid mounting the water bowl in the middle of a bare, smooth wall.

FOOD BOWLS:

Next on the list are food bowls. While we will cover diet shortly, you have the option of using either arboreal-mounted or standard ground bowls. I primarily tong-feed mine, so I don't keep permanent food bowls in my adult enclosures. However, for hatchlings, I highly recommend using them. Baby monitors are naturally shy and may not be comfortable taking food directly from tongs right away.

MISTING SYSTEMS/MANUAL MISTING/FOGGERS:

First and foremost: DO NOT USE FOGGERS. They often lead to respiratory infections. Green tree monitors do not live in swamps; they live in tropical forests where air flow is plentiful. Good ventilation is absolutely crucial for any reptile enclosure, but especially for rainforest species.

Now that we have that covered, let's discuss manual misting versus automatic misting systems.

For my tree monitors, I use a combination of both.

I have a misting system that kicks on every day at midday for one minute, but I will also manually spray the plants and near the monitors themselves. My male actually enjoys the water spray, while my female does not. I adjust my technique for her so the water doesn't hit her face, but still pools on her hollow log for her to drink. They are intelligent animals, and the minute they see the spray bottle, they know exactly what it means.

How often should I spray/mist my green tree monitor? This depends on a few factors—such as your substrate and your local climate—so unfortunately, there is no "one size fits all" answer.

Disclaimer: I do not use hygrometers to measure humidity. I started off using hygrometers, but I found them to be fairly useless. The animal will tell you what they need. I have also learned that they don't necessarily need to be kept at a constantly high humidity; they just need proper hydration. Those are two very different things. To ensure my lizards are hydrated, I mist them at least once a day, aiming directly on or right next to the lizard. If the animal is skittish, I will spray the walls and branches instead so they can come out and drink the droplets later. This is also why I love automatic misting systems. While the monitor might get startled when it first kicks on, they quickly get used to it.

What automatic misting systems do I use? I used to use the MistKing system, and while they are great, they are very expensive in Australia. A keeper in a reptile Facebook group recommended the MIUS misting system. It is an Asian brand, but it has become my absolute favorite. I actually no longer own my MistKing because the MIUS system is far better for my needs.

MIUS Misting System PROS:

The water reservoir can be placed under the pump (unlike MistKing).
They offer various models with different strengths (for example, I have one pump running 7 enclosures).
PRICE! They are very affordable compared to other brands.
They produce a very fine mist, and replacement parts are cheap and easy to find.
They offer a variety of nozzle designs.

MIUS Misting System CONS:

You have to buy them from AliExpress or similar online websites.
Most models do not have an inbuilt timer (though this can be a pro or con depending on your setup).
If you keep the water reservoir above the pump, the nozzles might drip.
Plug type: unfortunately, you will need to buy a wall adapter.

Regarding the lack of built-in timers, I actually prefer that the bigger models don't have them because I connect them directly to my ARLEC Grid smart home system. I use the Grid system for all my light and misting timers. The only downside is that you can only adjust the Grid timers in one-minute increments. For instance, you can set the misting system to turn on at 12:00 and off at 12:01, but you can't do shorter bursts. To get around this, I simply adjust the number of nozzles I use. For a hatchling enclosure, I will only use a single nozzle rather than a double nozzle, so that one minute of spraying doesn't flood the enclosure.

I buy the GRID timers from Bunnings.

SUBSTRATE:

Substrate is another highly variable topic. Keepers use everything from bark chips to a fine coir peat mix to natural potting soil.

I keep my adults in fully bioactive setups, but for babies, simple is best. I highly recommend against using fully planted bioactive enclosures for hatchlings, though you can certainly still add isopods and springtails to their substrate to act as a cleanup crew.

My preferred substrate is a custom bioactive soil mix consisting mostly of natural soil (strictly without fertilizers), combined with sphagnum moss, coir, and a tiny bit of charcoal. To be completely honest, there is no strict recipe, but a great starting ratio would look like this:

30L of natural soil
15L of hydrated coir
100g of sphagnum moss
100g of crushed charcoal

When setting up bioactive substrates, most tutorials will tell you to use a drainage layer or "false bottom," usually made of LECA clay balls. DO NOT USE THEM. I had an adult female dig down and eat the LECA balls, even though they were buried under 20cm of substrate.

I cannot stress this enough: DO NOT USE LECA CLAY BALLS, and avoid pebbles as well. I have actually completely stopped using false bottoms and now just provide a single, deep layer of substrate.

For babies, however, do not use a deep substrate layer. A thin layer of 3 to 5cm is plenty.

A skittish hatchling will often burrow deep into thick substrate to hide, which will inevitably give you a heart attack trying to find them!

HEATING:

Heating is arguably one of the most important care requirements. Unlike a lot of Australian monitors, this species doesn't need a super-hot basking site.

Hotspot Temperature: 35–40°C. This temperature range seems to work best. If the hotspot is too hot, they will often only bask for a few minutes before moving away to find a cooler spot.

Hotspot Placement: Use the highest, thickest branch. Ideally, you want about 15–20cm of clearance between the light bulb and the basking spot, which allows them to stand up without getting burned. I never mount lights inside the enclosure. Given the very high price tag of Green Tree Monitors in Australia, I do everything possible to limit the risk of injury, especially burns.

Heat Bulb Types: Daylight basking bulbs are fantastic, but you need to avoid basking spot lights, as they tend to produce a narrow, concentrated beam of heat rather than a wide, even spread. I use radiant heat with the majority of my other snake and monitor species. However, I noticed an interesting behavior with hatchling GTMs: they initially had trouble finding the invisible radiant heat. Once I switched to a daylight-emitting basking bulb, they found it quickly. Radiant heat is still great, but this is a worthwhile observation for babies. My adults don't seem to have this problem.

There are no particular brands of lights that are definitively "better" than others—it mostly comes down to personal preference. I actually use an inexpensive brand called NOMOYPET. It has mixed reviews, but at under $10 a bulb, the occasional blowout is nothing compared to spending $20+ on premium bulbs that might only last a month anyway.

What wattage should I use?

This depends on a few factors, including the distance from the light to the basking spot, your room's ambient temperature, and the specific type of bulb. My best advice is to start with a middle wattage—for instance, if your options are 50W, 75W, and 100W, start with the 75W.

Always have the enclosure completely set up and running for at least 1 to 2 weeks prior to bringing your monitor home. This gives you time to thoroughly test and dial in your heating, misting, and overall parameters before the animal arrives.

Thermostats:

As a general rule, all heating should be connected to a thermostat. Experienced monitor and dragon keepers know that you can sometimes find the exact perfect wattage bulb to naturally maintain the correct basking temperature without a thermostat. However, I absolutely do NOT recommend doing this for your first Green Tree Monitor. You always want to err on the side of caution. Always. It is much better to be safe than sorry.

I personally use Inkbird ITC 308-Wifi thermostats for all my reptiles. You can control them from your phone AND they link to the GRID Connect app.

Important to note this is an ON/OFF thermostat and not a dimming one.

UVB:

UVB is extreamly important for all monitor species and green tree monitors are no exception.

Why UVB is Non-Negotiable:

For monitor lizards, UVB lighting isn't just about recreating natural daylight—it is a biological necessity. Here is exactly what it does:

Vitamin D3 Synthesis: When a monitor's skin is exposed to UVB radiation, it triggers a chemical reaction that allows their body to naturally synthesize Vitamin D3.

Calcium Absorption: This is the crucial step. Without adequate Vitamin D3, reptiles physically cannot absorb the calcium provided in their diet; it simply passes right through their system.

Preventing MBD: A prolonged lack of UVB leads to Metabolic Bone Disease (MBD). Starved of usable dietary calcium, the lizard's body begins pulling it directly from its own skeleton, resulting in brittle bones, severe physical deformities, tremors, and eventually death.

Behavior and Vitality: Beyond bone health, proper UV exposure stimulates natural circadian rhythms, encouraging active hunting, regular basking, a healthy appetite, and a robust immune system.

Dialing in the Right Output:

Since Green Tree Monitors are an arboreal rainforest species, they naturally receive dappled sunlight filtering through the canopy, rather than the intense, direct radiation a desert species would endure.

Because of this, you do not want to use a bulb with too high of an output. I highly recommend the Arcadia T5 6% or the T8 12% to perfectly mimic their shaded forest environment.

Sizing and Setup

The size of the bulb and fixture will depend entirely on the length of your enclosure. I always try to match the bulb length to the enclosure itself—for instance, a 90cm wide enclosure will get a 90cm UVB tube.

Arcadia has a fantastic lighting guide with lots of detailed information on their website. Click the button below to check out their species-specific lighting guide:

Arcadia Lighting Guide

Lighting:

On top of UVB, you can also use various LED lights. You can use high tech LED lights like the Arcadia Luminize or cheap LED lights from Bunnings.

For hatchlings, the uvb is generally enough light so you may not need anymore lights.

Cameras:

Security cameras are an incredible tool to help you literally monitor your monitor (pun intended!). There are many different brands available on the market. I personally prefer Eufy cameras, but Tapo is another highly recommended option. You can mount the camera directly inside the enclosure or set it up outside facing the glass.

Cameras are a fantastic tool, especially for skittish babies. They allow you to observe their natural behaviors, ensure they are eating, and confirm they are utilizing their basking spots without you physically being in the room and spooking them into hiding. This massively eases the keeper's anxiety. While the monitor might initially be wary of the camera unit itself, they quickly accept it as just another part of the enclosure furniture.

Step 2- Diet

Diet is one of the main challenges new Green Tree Monitor keepers face.

With many reptiles, keepers use higher-protein diets and frequent feedings to make the animal grow much faster. While this "power feeding" method comes with severe health risks like obesity, it unfortunately remains very common in the reptile hobby.

Green Tree Monitors are largely insectivorous. Hatchlings, in particular, cannot tolerate large quantities of protein and fats in their diet; some have unfortunately DIED from gout due to this exact issue.

IMPORTANT NOTE: I understand the desire to see your monitor grow quickly, but you risk killing them if you regularly feed high-protein meals like rats, mice, quail, egg, mince, or dog food. Green Tree Monitors are not a species you can rush to breeding size, so you must completely remove that mindset.

For this section, we are strictly focusing on hatchlings up to a year old. A monitor's diet changes significantly as they grow, and we will cover adult diets later.

Staple Diets:

These should be offered every 1 to 3 days (I tend to feed my babies every 2 to 3 days):

Crickets
Roaches
Grasshoppers
Mealworms
Black Soldier Fly Larvae (BSFL)
Stick insects

Every monitor will have its own preferences. Unfortunately, mine absolutely will not touch mealworms or Black Soldier Fly Larvae. My babies primarily feed on woodies and crickets.

Disclaimer: This should be self-explanatory, but DO NOT feed wild-caught bugs to your monitor. Always ensure you are using captive-bred feeder insects.

Occasional Feeds:

These items can be offered sparingly, about once every 1 to 2 weeks:

Chicken or turkey mince
Chicken hearts and giblets
Egg (raw or cooked)
Fuzzy mice
Rats (though I would avoid pinkie rats)
Day-old quail

Egg and chopped up quail is my preference for the hatchling tree monitors.

Suppliments:

Since a Green Tree Monitor's diet consists mainly of insects—which naturally lack a perfect calcium-to-phosphorus ratio—proper supplementation is absolutely crucial for healthy bone growth and preventing Metabolic Bone Disease (MBD).

I recommend lightly dusting their feeder insects with a high-quality Calcium + D3 powder once a week for one of their meals. Make sure to only dust them lightly; you don't want the bugs looking like heavy white ghosts, or the monitor may refuse them.

Some Green Tree Monitors can be incredibly picky and will outright refuse bugs if they taste the calcium powder. If you run into this issue, a highly effective trick is to mix the required dose of powder into a small amount of raw or cooked egg. The egg completely masks the powdery texture and chalky taste, and because egg is such a high-value treat, they almost always lap it right up without hesitation.

Here is a sample weekly feeding schedule you can use as a template (without the suppliments):

This feeding schedule represents the absolute maximum frequency I would recommend for offering a protein-heavy diet. You can also stretch this out and use it as a fortnightly schedule instead as pictured below:

Welcoming your Monitor home!

Now that your setup is completely dialed in and you understand their dietary needs, you are finally ready to bring your Green Tree Monitor home!

While this is an incredibly exciting moment for you, remember that relocation is extremely stressful for the lizard. Because of this, it is crucial to make their initial introduction to the new enclosure as smooth, calm, and hands-off as possible.

Pick the Room:

When your Green Tree Monitor first arrives, you will need to safely remove it from its transport container. Ideally, do this in a small, completely secure room where there is no chance of escape—such as a bathroom. A large, open space like a reptile room or lounge room is not ideal. If a flighty baby gets loose in a big room, you will have a very hard time catching it, and the resulting chase will severely traumatize the lizard. Choose your unboxing room wisely!

Inspect the Lizard:

Once you are in your secure room and open the container, you need to assess the lizard. If it is skittish, pick it up carefully but with a secure grip. They are incredibly fast and can contort their bodies easily. However, if you are getting a well-handled, socialized baby, you do NOT want to grab and restrain it firmly, as this will immediately break trust. (Always ask the breeder how they raise and handle their babies so you know what to expect). Make sure you check for any stuck shed, parasites ect.

Putting the lizard away:

Now that you have inspected your baby lizard, you will need to place it into its new enclosure. This transition is extremely stressful, and they will often try to bolt. For this reason, make sure you do not have both enclosure doors open at the same time.

If you are using a single-door enclosure, reach the hand holding the lizard inside, but do not release your grip just yet. Pull the door closed against your arm as much as possible to block any escape routes, and then slowly let go of the lizard.

At this point, the lizard may sit on your hand for a few moments to process its new surroundings, or it might instantly bolt into the foliage. Regardless of what it chooses to do, you must remain completely STILL. Wait until the lizard stops panicking or begins slowly walking around the enclosure, and then withdraw your hand incredibly slowly. The slower you move, the better. Slow, predictable movements are much easier for a monitor to track, which significantly reduces the chance of triggering another panic response.

First 1-2 Weeks:

The first two weeks will depend entirely on your monitor's individual personality. They are highly unique animals, and their reactions to a new environment will fall somewhere on a spectrum:

Confident Monitors: Bold lizards might be out basking within the first few days, or sometimes even on the exact same day you bring them home. They will often readily accept food from tongs almost immediately.

Shy Monitors: Unfortunately, with skittish individuals, you may not see them at all for a while. Do not panic if you haven't seen your lizard in a few days. For these shy monitors, escape-proof feeding bowls are essential since they likely will not accept food from tongs right away. Simply leave their insects in the bowl and inspect it daily to confirm they are eating.

As mentioned previously, this is where having a camera set up from the get-go becomes an incredible asset. If you have a highly secretive baby that hides whenever you enter the room, checking the camera footage might be the only way to ease your worry and confirm they are actively basking and eating when you aren't around.

Common Health Concerns: