+1 on what Stephanie said.
If you're limited to what you're saying there with that stores "selection" it may be worth while to you to look here; super quality and good prices and if you buy a bunch plants free shipping Sweet Aquatics
. That is where I get all my plants for all tanks from and I don't even bother looking no where else any more.
Is this the fern you have in your tank? http://www.reptiledepot.com/New%20Folder/plant7.jpg
Then your best bet is to either keep it as a houseplant or give it to a terrarium owner as it will not last fully submersed.
Why they started selling non-aquatic plants as aquatic plants is beyond me to understand....But that's why there's forums like us that help you know what to watch & shop for