So I was browsing my craft store yesterday and I saw these "vases" that look more like 1 gal. goldfish bowls.
I then thought, "gee, I bet people have used Bettas for weddings". Sure enough, a Google search later that evening proved my hunch correct.
Then, I thought, "well, I don't see an inherent problem with using Bettas for a one-night wedding reception." I mean, the temperature indoors (oh yes, I'd have mine in a ballroom) can be regulated, so heating isn't too much of an issue.
My idea was to use a large, square vase, 1 silk (fake) flower, decorative pebbles at the bottom and just one Betta per vase (NO floating candles).
I figure if I did that for my wedding (in the far, FAR future), I could rescue a few Bettas of my own and then send one or two guests home with a Betta care booklet of some sort and Betta food.