Metabolic Bone Disease in Bearded Dragons
| Root cause | Insufficient UVB / calcium deficiency |
Root cause
Without sufficient UVB exposure, a dragon can't synthesise vitamin D3 needed to absorb dietary calcium, so bones progressively demineralise even if the diet looks calcium-rich on paper. A correctly specified T5 HO UVB tube, positioned close enough and replaced on schedule, is the real fix.
Early signs
Watch for a slight limp, hesitancy to bear weight, a soft lower jaw that flexes under gentle pressure, or twitching in the toes — MBD is far more treatable caught early than after visible bone deformity sets in.
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A single adult bearded dragon needs a minimum 4ft x 2ft x 2ft enclosure, with 6ft x 2ft x 2ft increasingly recommended as best practice — plus a linear T5 HO UVB tube, an overhead basking bulb on a thermostat, a real thermal gradient, a sturdy basking platform, and a shallow water dish.
A complete bearded dragon setup needs a 4ft+ enclosure, a linear T5 HO UVB tube, an overhead basking bulb on a thermostat, two thermometers, a basking platform, a hide, a shallow water dish, and age-appropriate substrate — all running and stable for at least 48 hours before the dragon arrives.
Hatchlings can start in a 20-gallon long tub, juveniles need to move to roughly a 40-gallon breeder footprint by a few months old, and adults need a minimum 4ft x 2ft x 2ft enclosure, with 6ft x 2ft x 2ft recommended.
Basking surface temperature should run 95–110°F depending on age (hotter for hatchlings, cooler for adults), with a cool side around 75–85°F, all provided by an overhead basking bulb on a thermostat — not a heat mat or heat rock.
Bearded dragons need a linear T5 HO UVB tube at 10.0 or 12% output, running the length of the basking third of the enclosure with nothing between bulb and dragon, replaced every 6–12 months regardless of whether it still produces visible light.
Bearded dragons should be kept at roughly 30–40% ambient humidity. Sustained humidity above 50% significantly raises the risk of respiratory infection in this dry-climate species — brief daily misting or a shallow soak handles hydration and shedding needs without pushing ambient humidity up long-term.