I tried coco fiber when I first bought Kadesh-back when he was small enough to fit in the bottom of a dainty teacup (now he could swallow the teacup!)-and it had a sour smell to it. I think I might have been over-misting though, too. I was going to try soil, but I like being able to see the colouring and markings of my frogs, and in dirt they get...well, dirty. Sounds dumb I know. Maybe I will try coco fiber again...