Help wanted

Well done, it's excellent you've managed to build him up as well as you have by the sounds of it!

Do you have much experience with reptiles or are you a new owner? I ask because people new to the hobby often have knowledge gaps (understandably) so sometimes don't have an optimum set-up.

Bearded Dragons are reasonably sensitive to environmental changes, for instance, moving from the pet store to a new home. That in itself causes many reptiles to go off their food but sounds like he was a poor eater before your intervention. Young animals in particular need psychological security in the way of a quite and calm environment (no traffic of people or animals frequently passing the enclosure, no noises etc), plenty of hiding opportunities and cover (hides, faux leaves and other decor for the Beardie to feel safe), and handling and disturbing only when necessary (only for treatment, water change and clean-out) to minimise stress as much as possible.

Inaccurate temperatures may also trigger a physiological slow down, in such a state the animal will not eat. Make sure that the gradient is 25-35˚C (77-95˚F) (cold end to warm end respectively) with basking area of 38-42˚C (100-108˚F). A dimming thermostat will need to be hooked up to the spot lamp with the heat sensitive probe positioned by the hot spot. Digital thermometers are also required to monitor temperatures and make sure nothings gone wrong. The spot lamp is usually positioned over a raised platform or something like a branch is placed underneath so the animal is elevated towards the heat source (usually 6-8 inches away). Adjacent to the basking lamp is a specific UV-B light which gives of very little heat but provides the essential UV-B for D3 synthesis. Bearded Dragons, being 'sun-worshippers' would yield more sufficient levels of D3 from light than orally administered D3, they would also be able to better regulate internally synthesised D3, thereby preventing the possibility of an overdose. It is important to position the UV-B light and heat lamp close together as D3 synthesis is a temperature dependant process.

How are you administering his food and is he putting on weight with it? Baby food is a good starting point but obviously isn't nutritionally balanced for beardies and may cause nutritional related issues further down the line. You could possibly try making your own formula with blending vegetables such as butternut squash, spring greens, carrot etc and some insects too, including phoenix worms, horn worms and silk worms (if you can get any), crickets, locusts and mealworms. Young Beardies usually favour more of an insect based diet as they require the extra protein for growth, but favour more vegetables once they mature. Here's a list of various vegetables you can try feeding him... reptile-savvy.weebly.com/vegetables.html

With his baths you can add Critical Care Formula, even if he doesn't drink it directly he will absorb some of the treated fluid through his cloaca. Alternatively it can be administered via syringe or gavage tube. This will provide him with additional protein and help prevent his muscles from wasting during his period of anorexia. Another good formula to use is reptoboost, you could alternate bathing in CCF one day and Reptoboost another or simply add to his drinking water. The reptoboost stimulates appetite and supports the uptake of nutrients when he does eventually eat.

I'd suggest getting him looked over by a reptile vet to check for signs of any other nutritional related disorders and anything else that may be putting him off his food, such as infection. If there's anything else physically wrong with him then optimising his environment may not be enough to get him eating again.