I just uploaded a video if them. It's hard to focus the camera because the glass has a bunch of scratches but you can kind of see them. His substrate is coconut husk. Besides the fibery bits, it also has some chunks in it. I bought it in a large bag at a reptile store a few months ago. When I I itially put it in, I didn't need all of it so I held on the the left over and used it to replace the old substrate when I cleaned out his droppings. A couple of weeks ago, I took out half of his entire susbtrate and put in all of the left over. It's probably half old, half new now but until an hour ago I never saw anything crawling in his cage. I haven't seen any ON him since I noticed them about an hour ago. He ate his two mice and went back in his hide. It's hard to see if they're on him because he only stuck his head out for the mice and I don't like watching him kill them so I went in the hallway and when I came back, the mouse was gone and he was already back in his hide :/