I found another guppy fry in the 29G today. That makes 8 total, plus I saw a few get devoured by my Gourami.
I'm starting to think that there's no way all of these fry were able to hitch-hike in on the plants I bought... so, off to read about sexing Guppies I go. Maybe I have a female in my school of 7?
I haven't started researching Ripariums yet, but I'm pretty sure that's what I want to do.