I personally find threads like this interesting. I just recently switched my Pyxie to water and she's been doing so much better then when on coco fiber. I'm not saying water is the answer for pac's, but the change just made me question coco fiber in general. I wonder how much they "require" a burrowing type substrate. I can't argue that they aren't built for it, but wonder if there's other ways of housing them with fewer issues. I keep my pac on water/moss/gravel and he doesn't burrow down like he does when hes in coco fiber. He loves his swimming pool, and just digging half way into the moss. Keep in mind I feed in a separate bin. When I had him in the coco fiber he would disappear. I feel like they get some kind of instinct to go down deep in that stuff because it's so fine. I'm not sure what the best is, all I know is I question coco fiber.