For some reason I thought this said banana plant because apparently I mix up banana and umbrella. lol. Though it got me excited because my petco recently started getting them in their loose plant tank and I got one and it is actually growing! But yeah, umbrella can't be submerged.
Not sure if you can take it back, but it does make a nice house plant. Don't feel too bad. I just bought some aluminum plant. Yeah, that ain't aquatic at all. lol.
Remember that the tank your fish lives in is his or her's whole world. Ask yourself this question, and answer it honestly: would you choose to live there?