Sounds like white water lily, Nymphaea odorata. You need to get some of the rhizome (the thick "bulb" under the mud) to grow a lily plant. I personally don't worry a bit about parasites or pathogens that will affect my fish coming in on plants. You are likely to introduce some algae, though; a good peroxide bath will kill off algae and other microbes.
Lilies do need a lot of light and nutrients to do well. If you think your tank can provide that, pot up a rhizome and see how it does. You can always throw it away if it fizzles. Don't throw it back in the pond- re-releasing plants is just as bad as re-releasing fish.
Lilies do need a lot of light and nutrients to do well. If you think your tank can provide that, pot up a rhizome and see how it does. You can always throw it away if it fizzles. Don't throw it back in the pond- re-releasing plants is just as bad as re-releasing fish.