If you're buying from the store (or even a lot of the big frog vendors purchase wholesale plants from large suppliers) I would wait at least a month for any systemic pesticides to wear off (systemic means it goes inside the plant, into the cells, and no amount of washing will get rid of it, though wash anyway to get off any soil and whatever is on the surface of the leaves). As for pothos, it's probably going to swallow the other plants you put in your tank, when people use pothos in a vivarium, it usually ends up being only pothos because it will strangle everything else in there. The Pilea is good, can get a bit leggy eventually, but you can always pinch it back, Streptocarpellas are awesome gesneriads that we grow in hanging baskets at the school, but can be kept tiny with trimming, and Neoregelia dungsiana gets to about 3"-4" and forms nice little clumps. I try to get a good mix of plants when I'm doing a tank, a few broms (I like to do the same kind of brom in a tank though, looks more natural to me than the people that do 10 varieties of colorful broms in a single tank), some vines up the back wall or climbing the wood, a few epiphytes for up on the branches, one or two ground covers, and some larger filler plants for the mid to back area (your Pilea would fall under that category). Feel free to ask away on the plant questions, I grow this stuff for a living![]()