The plant is Dracenia Sandriana 'white'. Its not a true aquatic plant, the shops usually sell them as 'potted plants', if they have more expensive plants there then they will more likely be the true aquatic plants like species of Anubias and Echinodorus or Amazon Sword, they are quite hardy plants that the plecs should leave alone.
Oh and in your new picture, you have Dracenia Sandriana 'red' too, thats not a true aquatic either, your best move would be to take it out and plant it in a plant pot and water it every day or every other day, they like lots of water but not being submerged, keeping them completely underwater, for lack of a better term... will actually drown the plant! They will start rotting down.
Answer is... dont go for the cheapest plants the shop has and ask questions, ask if they are true aquatic or not!
Plants like dracenia are usefull if you have fish like goldfish that are going to wreck the plants whatever you have and you know you are going to replace them regularly anyways.