Actually on contrary chardzard
, Amazons love full to moderate lighting. They like to be planted fully or mostly planted with some roots showing. With the right care and fertilizer an Amazon Sword can be a giant center piece to an aquarium. They are one of the common hardy plants so they can just about last anything.
i ask if you can post a far away pic because from this point of the pic the plant looks to be dead already, you will need to check and see if theres any new leave sprouting from the middle of the plant. Also if the whole plant(leaves, roots, stems and base(the crown) of plant) is brown except for that one part of the leaf then the plant may already be dead.