It has been in the tank for a couple of months. Has been sending out new leaves pretty regularly. Even sent out a shoot that looked like it might flower. And yes, the lights are on, although they are pretty dim. Think it is just a lack of light? Because everything else seems to be growing very nicely with the amount of like it has.
I can't see the stems from the picture but the leaves leaves look exactly like aponogeton, the shine from the leaves as well. It's a very silky looking plant. Another picture would clear my confusion