My terrariums usually bit the dust after a couple of years. I noticed he used compost, not potting soil. As one of the commenters said, there were probably lots of nice micro-organisms in that compost. I wonder how long it would last with a little animal in there, like a little salamander. Hmmmm....(brain working feverishly)....OK, I won't try it. A betta in a vase with a peace lily is about as far as I will go, I guess, lol!
i had a betta in a vase a few years ago. my cat at that time used to sit by the vase and take a drink, never bothered the fish though. anytime you had a glass of water she's sit and take a drink from it too. she was a good cat and never took much interest in my fish-just drinking their water if it was accessible. this latest pair of kitties like sitting on top of my tanks and watching their daily dose of Cat TV from all angles. if they had their chance they would go fishing.
i'd love to have one of those huge bottles to make a terrarium like that. makes sense to put compost instead of the sterilized soil like i had been taught to use as a kid making one using a soda pop bottle. i can't remember how long that one lasted but knowing my mom she threw it out at some point when she thought it had died or was taking up too much space for her liking.