I was breaking down my planted 75 gallon terrarium that has been ignored since summer and found some interesting things. This was a tank that I had designed for darts but never used since it was so big. I have moved and left it at my mom's house since my apartment is small. It has been in a sunny room that stays pretty cold and pretty much took care of itself since it was plants only.
We placed a baby red salamander that we had found on the farm in there just to see how it would do and of course it buried itself somewhere and you never saw it again. This was about a year ago. Then over the summer a Grey Tree Frog moved in to the house and promtly took a liking to the tank. Well sure enough we found them both alive and well today. The Salamander has more than doubled in size and the tree frog was huge and fat. There are lots of spiders who moved into the tank as well as natural bugs in the soil, so this was a complete ecosystem it seems. I haven't even been spraying this tank, but the substrate stayed moist. It was a unique mixture that I made up of leftover materials like Pealite, Vermiculite, Flourite, organic potting soil, and some gravel.