I did wonder at that! But loving my computer.. zooming in on the photo makes me think their is a variety of Sword at the back behind what I think is a bunch of vallis. Seen in a few darker green leaves to the right but notably the tall leaves at the top
A disappearing post suggested Aponogeton natans, but the pictured plant looks like a rosette plant, and the A. natans appears to be a type of plant that grows like anubia.