Resurrecting Golly thread! I've got two male guppies (feeder aka wild guppies) and six female mollies (one looks like pure yucatan, the rest appear to be hybrids) in an 18gal tank. It will be awhile before the old DNA is guaranteed to have expired, but we'll see what happens in the mean time.
For the record: I bought small guppies to help reduce barbed gonopodium damage, and found the closest thing I could afford to wild type and out-bred mollies for better genetics. The huge green molly was from my LFS and was the only one not wasting away in pure freshwater, but had a cloudy eye. A little sea salt perked her right up and the tank is now light brackish. The other, smaller mollies were free from someone who had too many. They look to be at least 50% p. verifera, but a few of them definitely have some latipinnis in them. Dorsal ray counts are all over the spectrum and colors vary from dull gray with stripes to neon jewels and purple sheen. Nice, wide genepool was the goal here. With live foods, algae wafers, etc., I think I have a good shot with this mix. Suggestions? Opinions not yet stated? BTW, my LFS wants some if they happen. So does the lady who gave me the mollies.