From idea to terrarium: a home for Thamnophis sirtalis similis
Although my interest in Thamnophis species developed as early as the late 1990s, it took a long time before I actually kept these fascinating snakes myself. Instead, other species such as Pituophis, Elaphe, Boaedon and several more accompanied me over the years. It was not until the first half of 2025 that a group of 2.1 Thamnophis sirtal is similis (Fig. 01) finally moved in with me – and since then I have been asking myself again and again: Why not sooner?
Although I had already read a lot about the lively and curious natur e of garter snakes, I was not aware of how incredibly entertaining and interesting these animals actually are. Compared to most other snakes in my care, Thamnophis are exceptionally attentive: I can hardly walk past the terrarium without the animals curiously raising their heads. Fig. 02
Even after six months, this behaviour has not changed. All three are excellent eaters, and the female reached a body length of almost 60 cm at the age of only eight months. This prompted me to start planning a suitable terrarium. Their pronounced curiosity and the proximity of this species to water, which is often emphasised in the literature, had a decisive influence on my considerations.
As I am purely a hobbyist and do not work with my animals scientifically, the garter snakes take a back seat in this article. Of course, I designed the enclosure to suit their needs, but the terrarium is also suitable for many other species, as it is ultimately a tried-and-tested standard tank – functional and without any special technical features. The topic of lighting is also secondary; here, everyone must follow their own principles. For this project, I only used three LED ‘cabinet lamps’.
Material selection and construction
Despite the relatively moderate final size of around 70 cm, I opted for a terrarium measuring 120 × 50 × 50 cm – whether this will suffice in the long term remains to be seen (I am currently leaning towards 150 x 60 x 60 cm, as the animals have a strong urge to move around and it is simply more enjoyable to look at a large area). Due to the good price-performance ratio, I chose 19 mm thick furniture boards. They offer both stability and sufficient insulation. The quality of the coating is crucial; I opted for white as it allows for better light reflection. Since I later sealed the lower third with epoxy resin and sealed all edges with silicone, a poor-quality coating would be disadvantageous in the long term: moisture would inevitably cause the wood to swell. Alternatively, high-quality plastic panels would also be suitable, and in fact have even more advantages – but I wanted the terrarium to blend in visually with my existing setup.
The cut-to-size panels are easy to assemble using universal screws as shown in the accompanying illustration (Fig. 03). Before assembly, I drilled recesses for three LED lamps and the heat panel cable into the rear wall. During assembly, I initially left the lamps and heat panel hanging loosely and only secured them once the basic framework was in place. Pre-drilling the ventilation holes is also much easier. Using a 5 cm hole saw, I placed them on the sides – at the bottom on one side and at the top on the other – to ensu re good air circulation. The specific placement can vary, but it is crucial to ensure adequate ventilation without waterlogging.
After assembly, I sealed all corners and joints inside with aquarium silicone. If you want to use epoxy resin as well, you should apply it before the silicone, as resin does not adhere to silicone. Visually, silicone can be easily applied over the dried resin later. One or two coats of resin in the lower third are sufficient. During the drying phase, I installed stainless steel grilles over the ventilation openings and the guide rails for the glass panes on the inside and outside. Once the terrarium was completely dry and in place, I began setting it up.
Structure, design and habitat reference
A terrarium should offer the animals as much usable space as possible – for example, through levels, branches or places of retreat. Even though tastes vary, as a keeper I feel the need to do right by my animals as much as possible. For me, this includes hiding places and visually protected areas. The blue-striped garter snakes mainly originate from regions of the Gulf Coast of Florida. Accordingly, I studied numerous habitat photos and found the same elements time and again: tall grass, rocks, bodies of water and dense undergrowth. From this, a concept gradually developed.
Heat source: Heat panel and rock replica
I prefer heat panels as a heat source. The heat comes from above, the substrate remains cool, and the risk of burns is minimal – I have not had a single case in over ten years. Panels with low wattage but a large surface area keep the surface temperature below 45 °C, while 10–15 cm below, temperatures of around 30 °C are easily reached. The 38-watt panel (40 × 40 cm) used, with thermostat control, allows for a temperature of around 31 °C at the heat point and a temperature gradient of up to around 23 °C – the latter depending on the ambient temperature (in my case, approx. 21 °C). In order for the snakes to use this heat point, they need places to sit about 10–12 cm below the panel. To achieve this, I made an artificial rock out of polystyrene sheets, tile adhesive, heavily diluted acrylic paint and finally epoxy resin:
Two polystyrene sheets (each measuring 30 × 30 × 5 cm) were glued together at right angles and shaped with a knife to create a natural-looking form (Fig. 04). After applying two layers of tile adhesive (Fig. 05), it was time to add colour: As I have no particular artistic talent, I diluted the acrylic paint heavily (approx. 1:500) and applied the mixture unevenly, causing the paint to spread like rainwater in natural structures. The base colour is a dark beige, and I dabbed the edges with olive green for a moss-like effect.
Important: The extremely diluted paint appears very pale at first (Fig. 06), but epoxy resin greatly intensifies the pigments (Fig. 07). Too much paint would therefore look unnatural. Three coats of resin were sufficient for the relatively small T. s. similis. Epoxy resin must be handled carefully and in accordance with all safety instructions; the result is a robust, moisture-resistant and completely safe surface.
I then screwed and glued the finished rock below the heat panel on the back wall (Fig. 08).
Parallel to the rock, a covering was created for the planned water basin – a 60 × 30 × 10 cm industrial tub, which will later serve as a drinking trough and bathing pool. The same technique was used as for the rock. In addition, I was able to make a wet box (a hiding place that retains moisture well) and a second smaller rock from leftover material. The advantage of the surround is that the tub can be easily removed for cleaning without having to rebuild the terrarium or disturb the substrate.
Fig. 09, 10
Decoration / Enrichment
Now came what I consider to be the most enjoyable step: decoration – which also serves as enrichment for the animals. The nature of the three inhabitants hardly limits me here, because no matter how many hiding places I provide, they still show themselves frequently. Therefore, I decided on a lavish arrangement of branches and plants. I only use washable artificial plants.
To attach them, I drilled holes in cut-to-size roof batten pieces, which serve as stands for grass-like plants in particular. I used a layer of soil and a layer of pine bark as substrate and added various pieces of wood and roots from the garden so that the animals can disappear completely if necessary.
Tastes vary – fortunately. But I hope I have met the animals‘ needs. Considering that the entire project cost less than 500€, the result is quite impressive.
I did not discuss the installation of a thermostat , as I use smart temperature and humidity sensors for my system.
Initial observations
The following values and behaviours have been observed so far:
– Without spraying, the humidity remains stable at around 60%.
– The temperature gradient during the day ranges from 31°C at the warmest point to around 23°C in the cooler area.
– Resting on the rock is often followed by a short dip in the water basin.
– The artificial rock under the heat panel is used intensively almost every day, but the wet box is hardly used at all.
– Cleaning is time-consuming, but takes only about 20 minutes per week.
– Despite numerous hiding places, all three animals usually come out curiously and observe the hairless monkey.
For those interested in building a replica, a list of materials with exact dimensions and brief assembly instructions are included in the appendix.
Simon Regler, Gartenstraße 9,
97262 Hausen bei Würzburg
ptyasimon@gmail.com
Material list for Thamnophis terrarium:
White furniture board, thickness 19 mm:
1 x top 1200 mm x 500 mm
1 x bottom 1162 mm x 462 mm
2 x sides 481 mm x 500 mm
1 x back 481 mm x 1162 mm
1 x top panel 1162 mm x 100 mm
1 x bottom panel 1162 mm x 100 mm
2 x 4 mm glass 630 x 270 mm
1 x PVC glass guide rail, bottom, 116 cm for 4 mm panes
1 x PVC glass guide rail, top, 116 cm for 4 mm panes
3 x LED lighting 15 W
1 x heat panel 38 W
1 x industrial tray 600 x 300 x 100 mm
12 x 53 mm stainless steel ventilation grilles
1 x temperature sensor
1 x beige acrylic paint, 1 x olive acrylic paint
32 x universal screws
15 x artificial grass tufts
2 m artificial ivy
Moss in the wet box (alternatively vermiculite)
Leaves, branches, roots from the garden (stored in the boiler room for a long time)
White aquarium silicone, tile adhesive, epoxy resin