The right terrarium: UVB, temperature and size

The terrarium is literally your reptile's habitat. Incorrect setup = illness. This guide covers the complete setup: size, UVB lighting, temperature, humidity, substrate and decoration.

Size by species

Minimum size by adult reptile:

• Leopard gecko: 60×40×40 cm
• Bearded dragon (pogona): 120×60×60 cm
• Chameleon: 80×60×120 cm (they need height)
• Royal python: 120×60×60 cm
• Adult green iguana: 200×100×200 cm (a whole room)
• Mediterranean tortoise: outdoor garden 5-10 m² + indoor winter enclosure 100×60 cm
• Aquatic turtle: pond or tank of at least 200 litres

General rule: the reptile must be able to stretch out fully + have a thermal gradient + hiding zones. Bigger is always better.

Lighting: UVB mandatory in many species

UVB enables the synthesis of vitamin D3 → calcium metabolism. Without UVB in diurnal reptiles:

• Metabolic bone disease (MBD)
• Deformities of the spine and limbs
• Spontaneous fractures
• Early death

Reptiles that NEED UVB:

• Turtles and tortoises (all)
• Pogonas, iguanas, chameleons (diurnal)
• Diurnal geckos
• Anoles

Reptiles that do NOT need UVB (or very little):

• Leopard gecko (nocturnal, but some vets recommend gentle UVB)
• Snakes (most)
• Boas

Top brands: Arcadia Pro T5 12% (desert) or 6% (jungle), Zoo Med Reptisun. REPLACE the tube every 6-12 months (it loses UVB effectiveness even though it keeps giving off light). Maximum distance to the reptile: 30 cm.

Thermal gradient

Reptiles are ectotherms: they need to move between warm and cool zones to regulate their body temperature. NEVER heat the whole terrarium evenly.

Zones in any terrarium:

• Hot zone / basking spot (under the bulb): 35–40°C for bearded dragons/iguanas, 32–35°C for geckos, 30–32°C for pythons
• Cool zone (opposite side): 22-26°C
• Night: 18-22°C (some need night-time heat with a ceramic emitter)

Equipment needed:

• Basking bulb of 50–100W depending on species
• Thermostat MANDATORY, connected to the lamp (prevents burns and overheating)
• 2 digital thermometers: one in the warm zone, one in the cool zone
• Night-time ceramic emitter if the species requires it

NEVER use heat rocks (they cause skin burns) or heat mats without a thermostat.

Correct humidity

By species:

• Pogona: 30-40% (desert)
• Leopard gecko: 40-50%
• Tortoise: 40-60%
• Yemen chameleon: 50-70%
• Royal python: 50-60%
• Tree frog: 70-80%
• Green iguana: 70-80%

A digital hygrometer is mandatory. Adjust with: daily manual misting, a water source, an automatic fogger system for humid species.

Substrate: the safe and the dangerous

Safe substrates:

• Kitchen paper (most hygienic, ideal for quarantine)
• Cypress or sabal wood chips
• Coir-soil (high-humidity species)
• Specific mix for tortoises (soil + sand)

DANGEROUS substrates:

• Cat litter: ingestion → intestinal impaction → death
• Calcium sand from the shop: same reason
• Corn cob pellets: moisture → mould
• Cedar: toxic respiratory fumes
• Pine chips: same reason as cedar

Functional decoration

It is not aesthetic, it is functional:

• 2-3 hides: warm zone, cool zone, humid zone (shedding)
• Basking branches: height to get close to the heat source
• Live/artificial plants: enrichment + humidity (arboreal species)
• Water bowl: cleaned daily
• Stone for filing claws (pogonas, iguanas)

Cleaning and maintenance

• Daily: remove faeces, leftover food, refresh water
• Weekly: clean food and water dishes thoroughly
• Monthly: clean terrarium walls with diluted vinegar + water
• Every 3-6 months: complete substrate change
• Every 6-12 months: replace the UVB tube

Estimated total cost

Complete initial setup:

• Leopard gecko: €200-300
• Pogona: €350-500
• Tortoise: €400-700 (plus outdoor space works)
• Chameleon: €500-800 (humidity makes it trickier)
• Green iguana: €800-1,500 (giant terrarium in adulthood)

Monthly maintenance cost: €20-80 depending on species (substrate, food, electricity for the lamps).

In summary: the terrarium is your reptile's life. Correct size + UVB replaced every year + a well-measured thermal gradient + appropriate humidity + safe substrate = a healthy reptile. A serious initial investment, but paid back over years of life free from illness.