2isgreen I have been very tempted to do this as well. Living less than a mile from two bayous i have thought about and almost done this numerous times. Also 10 minutes from the gulf of Mexico I have been intrigued by bobby rice and his experiments with saltwater fish in freshwater pond. All of this is why I delayed stocking last march when we bought the property.
Unfortunately I believe I am much too dumb to pull this off effectively without adding some unwanted species. I figure most experts will say the same about adding unwanted species unknowingly being the biggest drawback to this approach. However it is basically free and with small pond like you and I have if you later decide it does not work for you can always roetone the pond for about what it would cost to stock from hatchery.