Just a couple quick thoughts....
1. A 3 week old dragon needs to be eating a lot more then 3 to 10 crix every two days. At that age they should be easily eating 25 or more per day. Ours eat 50 to 100 a day.
2. 105 is to low for a basking spot. Increase a basking spot to 110 to 115 degrees (making sure the ambient cage temps do not exceed 90'0s on warm end and low 80's or so cool end). Young dragons need hot temps to increase appetite and stimulate feeding responses.
3. Increase your lighting. From that picture the cage looks to dark. If the cage is dark the dragon will not realize it's time to get up and move around. Combine that with low temps and your dragon will appear to brumate - even though he's not brumating, just has improper amounts of light and heat.
4. Switch off of sand and back to paper towels. At this age I don't recommend using sand, but regardless of what I think, he should be on paper towels or newspaper right now to monitor his stools and for ease of chaging/cleaning the tank if he's sick or has parasites.
At only 3 weeks of age it's pretty critical you get your dragon up to speed fast. Since he appears normal and everything when taken out of the cage, my guess would be your cage is too dark. Dragons need bright light to be active. When you take him out he may see more light or be exposed to that and it wakes him up.
Vet is always a good idea. I would get him to see one right away. But if nothing else, increase your heat/lights and i bet you will notice a difference. If you don't, he's probably got parasites or other problems and would need to be seen by a vet anyway.
brandon
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Dragons by Nature