Or does it have to be inside of water, if you plan on using it in a fish tank in the future?
I have a single Betta. I purchased a java fern as well as another type of plant and the second one polluted the tank because it wasn't meant to stay underwater. I read up on it and found that pet stores will sell these anyway.
Another thing. Beware of heaters you buy at the pet store. Try them out in a separate container BEFORE you stick them in the tank with your precious fish. I'm glad I did this because two of the ones I purchased went well over 100ÃÂº. I had to take them back. I use a digital thermometer to check the temps with.
Here are some links that might be useful.
All plant species (list)
Plants [Archive] - Aquarium Forum
Submerged and submersed. In nature aquarium plants grow mostly in submersed then submerged conditions. Bog conditions.