Hey, I agree with lissag25...It's too soon to worry about their behaviors as long as they are healthy. Every reptile enclosure is different and almost always needs some tweaking after they are set-up when the animals are living in there...unless you're a breeder and been doing it for years. The most stressful thing that happened to me was when I got this beautiful large simulated acrylic hollow tree stump from Petsmart. It looked attractive and I thought easy to clean and maintain. You can imagine my distress when my Ball Python took a climb inside of it! I had all those horror stories of snakes getting stuck in plumbing and whatnot come to mind. Well, after the snake came back out (whew), I filled and patched it so she would never do that again. I've had similar problems with amphibians crawling in behind waterfalls. Packing the backs of them with sphagnum cured that once the animal cleared out. I guess my suggestion here is that after a while, if the behavior doesn't change, consider blocking your cave somehow. Another aspect you might consider is that most of the information out there on any reptile almost always refers to adult specimens (the state they are in most of their lives). Sometimes the behaviors of juveniles are not fully stated or discussed. I suspect that young water dragons, like any immature reptile, has to depend upon camoflage and hiding to survive the predators...which I would suspect to be mostly birds and other reptiles. Your new dragons might be acting out this behavior and will "get over it" as they grow. My milksnake was always hiding and bit when handled as a young snake. Now he doesn't bite and likes to lay out in the open all the time showing off his beautiful colors which are awesome (he's still a nervous wreck though when handled, but I can certainly live with that). Keep observing and learning from your pets...they're putting on a show even when it seems like they aren't...you're doing a great job.