Get ready, here comes a lot of information
:
If the shaking you're referring to looks like little tremors in the head and limbs, it's probably from a calcium deficiency. It's the start of Metabolic Bone Disease (MBD), a condition similar to osteoporosis in humans where the bones become thin and rubbery. It can do permanent damage if it isn't corrected.
The first step is to go get a calcium supplement. Unfortunately, the pet store gave you some bad advice. Your baby needs to eat much more than 3 crickets a day, and these feedings should be dusted with a calcium supplement. You want to get a supplement that provides D3.
RepCal Calcium with D3 is a good supplement. As previously stated, a good
UVB bulb is needed to help your baby absorb the calcium. Dragons can create their own vitamin D when under UVB. The D3 in the supplement will help give him a little extra, but it does not provide all the vitamin D needed to absorb enough calcium to prevent MBD.
This was mentioned too, but I want to reinforce it: It DOES VERY MUCH MATTER which
UVB bulb you get. There have been tons of tests done on different bulbs and a lot of them are very harmful. They can cause blindness, lethargy, even death in some cases. The best bulb as of right now is the
ReptiSUN 10.0. It's very expensive in stores, but you can order it for about $20 here:
http://www.petmountain.com/product/reptile-fluorescent-bulbs/504983/zoo-med-reptisun-10.0-uvb-bulb.html
It is true that you want a temperature gradient in the tank, meaning one side will be cool and one side will be hot. Crickest gave some good advice. Most of us here have our basking lamp on one side of the tank and our
UVB light all the way across the back. Put something beneath the lamp for your baby to climb on, and
voila! You have a hot side, a cool side, and a basking spot.
Adding a good source of UVB and a calcium supplement will stop the shaking and increase his appetite.
(Since you just got him a week ago, he may be going through a bit of relocation stress as well, which will decrease his appetite. This can last up to 2 weeks, so don't be alarmed if he's not eating as much as he should.)