Weight scales are your dragons best friend. Weight scales are inexpensive, less than 1 Vet visit. Usually about $40 or less. You need one that has a capacity of at least 700 grams and measures in one gram increments at least.
Dragons generally can only lose weight in 2 ways. Dehydration and excrement. Water weighs 1 gram per milliliter. The tube of a standard eyedropper holds about 6ml. The weight of a large adult bowel movement can be as much as 20 grams.
A weight scale can help you manage how much live food to feed. If your dragon continues to increase in weight then you need to cut back on live food. Moreover, if your dragon continues to lose weight, despite an increase in protein, then you need to go to the vet. If your dragon brumates he should lose very little weight if healthy. If your dragon doesn't gain the lost weight right back after hydration I'd bring him to the vet.
That being said, if your dragon loses a sustained 20 grams or more, bring him to the vet.


