i keep natives, so naturally, native plants suit my tank well. i'm not sure where you're located geographically, but native plants would be fine if you collect them while the temps in your swamp/stream are the same as your tank. for instance, if you are in teh northern elevations like me, i wouldn't collect plants now in winter for a tropical tank. it never hurts to experiment - hell that's half the fun. your tanks isn't going to CRASH or anything. the owrst that might happen is you may have some critters come into your tank if you dont rinse well enoguh, but your fish will eat em. all i've ever done was rinse the plants off before adding to my tank. i have a great macroalgae in my tank now that's thriving.