Are they both in the same enclosure ?
Most likely it's relocation stress. To help the little guy out, use a large Sterilite container (you can put a screen over it if you need) and set up a heat light and UVB light temporarily. Put Bert inside by himself. The container will block his vision of everything around him and allow him to settle in a bit better. Offer him a soak in warm water no deeper than his armpits then place him on the basking site inside the Sterilite.i got them tuesday