Puff used to hang around under his basking lamp all day and would jump the second I dropped crickets in there. Now, he is very slow to get them but he does. He used to eat carrots all the time and he occasionally snacks on them. He now sleeps in the corner of his cage. He has little gnats that fly around his cage, regardless of how often I clean it because of the carrots in there. I am wondering if anyone has any clues as to what is going on?
Also, he used to snatch the cricket the first time he would spit out his tongue. Now it is almost as if his tongue lost its stickyness. He has proper temps etc.
Lethargy and sluggish movements can be a sign of many things.
My beardie has been behaving similarly recently, and I found out he had both pinworms and coccidia.
Taking a fecal sample to the vet could eliminate parasites. Trust me, if he has parasites, it's best to catch them early. Otherwise you might be stuck with months of treatment.
What type of UV do you use? What type of heat lamps? What are the temps?