Outdoor pond plants in a tropical tank?

[fantasy fish]

i went uptown with my neighbor to buy plants for her outdoor pond and we got an extra plant, i can't remember what it was called the the name included the word lettus. Anyways i am wondering if u can put these kind of plants in a tropical fish tank?

 

[Nyte]

If it's "water lettuce" you'll be fine. I have some in my tank. Grows really fast!

 

[fantasy fish]

k thanks i think it is water lettuce