The bark is nice. Especially if you go with a "forest" type theme for your terrarium, ad a (paper, outside) forest backgound, and maybe even a "stair step" type of thing going on in the back, some dry moss, etc. I've kept small garters in a 20 gal long setup like that, with a little clearing and a tiny focused basking light beaming in. For animals that like to burrow in the substrate, it's not a great choice though. It's a bit too pebbly. Go with the smallest size bark you can find and don't forget to make sure that the depth is appropriate.