Is a 40 gallon tank enough for a bearded dragon?

When it comes to housing bearded dragons, one of the most common questions is whether a 40 gallon tank provides enough space. Bearded dragons are active reptiles that require adequate room to thrive. While a 40 gallon tank may seem spacious compared to smaller enclosures, there are a few factors to consider when determining if this size tank is truly sufficient.

The importance of tank size for bearded dragons

Tank size is important for bearded dragons for several reasons. First, bearded dragons are active creatures that need adequate space to run around and explore. They are naturally inquisitive and like to climb, so cramped quarters can cause stress and boredom. Second, bearded dragons grow rapidly, especially during the first year of life. Babies and juveniles will quickly outgrow a small tank. Finally, tank size impacts factors like temperature gradients, UVB exposure, and husbandry. Larger tanks are generally easier to maintain at proper temperatures and provide greater exposure to UVB lighting.

General tank size guidelines for bearded dragons

There are a few general guidelines when it comes to bearded dragon tank sizes:

  • Baby bearded dragons: 10-20 gallon tank
  • Juvenile bearded dragons: 40 gallon breeder tank
  • Adult bearded dragons: Minimum of 75-120 gallon tank

These are minimum recommendations. Bigger is always better when housing bearded dragons, as it allows for more exercise and enrichment. Adult bearded dragons may require giant 120+ gallon enclosures to thrive.

Is a 40 gallon tank large enough for an adult bearded dragon?

For most adult bearded dragons, a 40 gallon tank is too small. While it may suffice temporarily for a young adult, bearded dragons will quickly outgrow this size. Adult bearded dragons should have a minimum tank size of 75 gallons, with 120 gallons or larger being ideal. Here are some reasons a 40 gallon tank is generally too cramped:

  • Limited floor space – A 40 gallon tank is usually 36″ x 18″, providing only around 5 square feet of floor space. Adults need room to roam and explore.
  • Restricted activity – There is little opportunity for climbing, burrowing, or other natural behaviors in a 40 gallon tank.
  • Narrow temperature gradient – A 40 gallon tank may only allow for a 20-30 degree gradient from cool to warm side.
  • Reduced UVB exposure – The compact tank size limits quality exposure to UVB light for vitamin D3 synthesis.
  • Difficult husbandry – Maintaining proper temperatures and humidity is harder in smaller enclosures.
  • Stress – Cramped conditions lead to higher stress levels and reduced well-being.

Overall, a 40 gallon tank severely limits an adult bearded dragon’s quality of life compared to more spacious options. While it may be suitable for younger dragons temporarily, an upgrade should be planned as they mature.

When can a 40 gallon tank be used for bearded dragons?

There are a few scenarios where a 40 gallon tank may work on a short-term basis:

  • Baby bearded dragons under 4 months old. But they will rapidly outgrow this.
  • As a temporary enclosure for juvenile dragons 6-12 months old. Still plan an upgrade.
  • Quarantine or hospital enclosure for sick dragons. Easy to disinfect.
  • Transport tank when moving house. Temporary housing.

A 40 gallon tank should never be considered a permanent home for adult or fully grown bearded dragons. But it can serve for interim housing in special situations for young dragons under 12 months old. Just be sure to provide an adequately sized enclosure once they reach maturity.

Best tank sizes for adult bearded dragons

To ensure proper housing for adult bearded dragons, aim for a minimum tank size of:

  • 75 gallons (48″ x 18″) – For one smaller adult dragon.
  • 120 gallons (48″ x 24″) – For one average-sized adult dragon.
  • 150+ gallons – For larger adults or multiple dragons.

The bigger the tank, the better for meeting an adult dragon’s needs. Long tanks provide more usable floor space for exercise and exploration. Tanks that are 48-72″ long are ideal for establishing a high quality temperature gradient and basking area.

Recommended tank dimensions

Some ideal tank dimensions for adult bearded dragons include:

  • 48″ x 24″ x 16″ – 120 gallon
  • 48″ x 24″ x 24″ – 180 gallon
  • 72″ x 24″ x 16″ – 125 gallon
  • 72″ x 24″ x 24″ – 190 gallon

Tanks with more depth (front to back) allow for deeper substrates for digging/burrowing. Prioritize floor space length and width first. Custom building oversized enclosures is also an option.

Other enclosure options

Besides glass tanks, other suitable enclosures for adult bearded dragons include:

  • Wooden vivariums – Can be custom built to desired size.
  • Melamine reptile cages – Durable and lighter weight.
  • PVC reptile cages – Budget-friendly option.
  • Stock tanks – Low-cost troughs and tubs.
  • Tortoise tables – Open-topped enclosures with privacy hides.

Custom DIY builds allow for greater flexibility in dimensions for bearded dragons. Just be sure any enclosure meets proper lighting, heating, ventilation, and substrate requirements.

Maximizing a 40 gallon bearded dragon tank

If limited to using a 40 gallon tank for an adult dragon, there are ways to maximize the usable space:

  • Use a front-opening tank for easier access.
  • Add climbing branches, hammocks, and platforms.
  • Incorporate burrows, tunnels, and hiding spaces.
  • Provide a deep substrate layer for digging.
  • Use a reflector dome lamp for focused basking area.
  • Situate decor along tank walls to open up floor area.
  • Offer daily outside-tank exercise time.

Enriching a small tank helps, but does not replace the need for adequate floor space. A 40 gallon tank should still only be viewed as temporary housing for an adult bearded dragon.

Potential issues with a 40 gallon bearded dragon tank

There are some distinct drawbacks and problems that can arise when keeping an adult bearded dragon in a 40 gallon tank:

  • Increased aggression and territorial behavior due to cramped space.
  • Difficulty regulating proper heat gradients across tank.
  • Limitations in providing adequate UVB exposure.
  • Higher risk of respiratory infections from poor ventilation.
  • Frequent substrate/tank fouling from confined space.
  • Reduced ability to find privacy/security when desired.
  • Excessive glass surfing indicating stress or escape attempts.
  • Obesity and other health issues due to inactivity.
  • Tail injuries and snout abrasions from rubbing along glass.

Bearded dragon owners should watch closely for any signs of stress, aggression, illness or injury if forced to use a 40 gallon tank long-term. Upgrading the tank size as soon as possible is highly recommended in these situations.

Tips for monitoring bearded dragon health in a 40 gallon tank

When using a 40 gallon tank for an adult dragon, here are some tips for closely monitoring health and wellness:

  • Weigh dragon weekly to track weight changes.
  • Inspect skin and extremities for injuries from glass rubbing.
  • Look for signs of stress like glass surfing or hiding.
  • Monitor temperatures daily across gradient and basking area.
  • Clean tank thoroughly twice weekly to reduce bacteria.
  • Provide exercise opportunities outside tank daily.
  • Book vet checkup at first sign of respiratory infection.
  • Upgrade tank immediately if aggression or health issues arise.

Catching any housing-related problems quickly is essential. Have an emergency plan for a larger tank if your bearded dragon exhibits issues in a 40 gallon enclosure.

Ideal tank setups for adult bearded dragons

To give adult bearded dragons optimal captive housing, aim for an enclosure that allows you to provide:

  • 75-100+ gallons tank size
  • 48-72″ long by 18-24” wide
  • Deep substrate for burrowing and digging
  • Temperature gradient from 80-110°F
  • Basking spot temperature of 95-105°F
  • UVB coverage across entire enclosure
  • Climbing branches, hammocks, platforms
  • Hides and visual barriers
  • Tank furnishings along walls to maximize open floor space

Aim to simulate key aspects of their natural desert habitat. Prioritize floor space, temperature ranges, UVB exposure, and opportunities for natural behaviors like climbing, digging and hiding.

Alternative solutions to a 40 gallon tank

Rather than squeeze an adult bearded dragon into a 40 gallon tank, some alternative solutions include:

  • Purchasing an adequately sized adult dragon tank (75+ gallons).
  • Building your own large custom enclosure.
  • Converting an old cabinet into a vivarium.
  • Connecting two 40 gallon tanks together.
  • Letting the dragon roam supervised for exercise daily.
  • Upgrading to a spacious bioactive vivarium.

With some creativity and effort, more suitable housing options can usually be found. Ask local reptile groups for cheap or free tank donations. Prioritize providing your adult dragon with enough room to thrive.


In summary, while a 40 gallon tank may seem like a large enclosure, it is generally too small to meet the needs of adult bearded dragons. These active reptiles require ample floor space for exercise, exploration, temperature gradients, and UVB exposure as they mature. Provide juvenile dragons with a minimum 40 gallon enclosure temporarily, but upgrade to a larger 75+ gallon tank as they reach adulthood. Maximizing the limited space in a 40 gallon tank can help in the short term, but monitor closely for any signs of stress or health issues. Be proactive in planning more suitable housing to ensure your bearded dragon’s wellbeing over its lifetime.

Leave a Comment