Bearded dragon lighting after respiratory infection

Bad lighting is the single most common husbandry mistake with bearded dragons — incorrect UVB or basking temperatures lead to metabolic bone disease and chronic illness that owners often don't notice until real damage is done. A respiratory infection adds another layer of complexity here: your dragon needs warmth to support immune function and recovery, but spiking temperatures or inconsistent gradients will stress the respiratory system further. To give you the right steer, can you tell me what size enclosure you're working with, what bulbs you're currently running (brand and wattage), and how old your dragon is?

Your vet gave you good advice. The ReptiSun 10.0 T8 is a decent UVB tube, but in a 4x2x2 the T8 format loses a lot of intensity across distance — by the time UVB reaches your dragon basking at a typical height, output is often well below what an adult needs. That low UVB means his immune system is running below par, which absolutely contributes to susceptibility to infections like this. The unnamed basking bulb worries me too — consistency matters a lot right now. During recovery, you want the basking spot sitting reliably at 40–42°C and the cool end staying around 25–27°C. Any hotter and you risk heat stress on already inflamed airways; any cooler and he won't mount a proper immune response. What's your current basking spot temperature measuring, and are you using a digital probe thermometer or the stick-on dial type?

The dial thermometers are notoriously unreliable — they can read 4 to 6 degrees low, so your actual basking temperature could be anywhere. That uncertainty is the last thing you need right now. Before I get to the UVB upgrade, grab a digital probe thermometer or an infrared temperature gun — the Etekcity Lasergrip 630 is about £12 on Amazon and will give you an instant accurate surface reading. It's essential. On the UVB side, the single most impactful change you can make in a 4x2x2 is switching to the Arcadia T5 HO 12% Dragon lamp with the Arcadia ProT5 controller. The T5 HO format pushes strong UVB down to your basking zone properly across that enclosure width, and the 12% output level is correctly calibrated for adult bearded dragons. Stronger, more consistent UVB directly supports immune recovery — your vet was right to flag it. Keep the basking bulb at whatever wattage holds that spot at 41°C once you've measured it accurately, and the Arcadia T5 kit will handle the rest of the lighting equation cleanly.

Both matter, but they work on different things. The antibiotics target the bacterial infection directly. UVB matters because bearded dragons synthesise vitamin D3 through skin exposure, and D3 is central to immune regulation — not just bone metabolism. A dragon running on weak UVB has chronically suppressed immune function, which is likely part of why he got sick in the first place and will affect how robustly he recovers. The Arcadia 12% T5 HO won't replace the antibiotics, but it removes a real handicap. Most owners see improved basking behaviour and appetite within a couple of weeks of switching to proper output T5 HO lighting, and both of those signal the immune system is getting the support it needs.

Exactly that. Get the temperature gun first so you know what you're actually working with on the basking spot before you change anything else — it takes five minutes and gives you a proper baseline. Then fit the Arcadia ProT5 kit with the 12% Dragon lamp. For a 4x2x2 you want the 39-watt 46cm tube if the kit spans the width, or the 54-watt 58cm if you can fit it. Mount it inside the enclosure or directly on top of a mesh lid with no more than 35–40cm between the tube and his basking platform. Run it on a 12-hour cycle. That combination, once your basking spot is dialled in correctly, gives him the best environment to finish his recovery and stay well going forward.