Caring for java fern in a home aquarium

[FunFish]

I recently set up my Betta tank with a Java Fern Pad that caught my eye.

It's been about a year since I installed it, and I've noticed it's been slowly melting away. Despite regular fertilization and experimenting with different lighting setups over the past few months, the melting persists. However, there's a silver lining - new, healthy leaves have started growing from the bottom, and they look perfect, unaffected by the melting.

I have two questions regarding this issue.

Is the melting due to the fact that the plant was initially grown emerged, and no matter what I do, these leaves will inevitably melt?

If I trim the melting leaves immediately, will it promote the growth of new submerged leaves, or will I end up with a bunch of rotting roots?

I've had java ferns do great in my tanks, until I had to treat for parasites. Copper in the water really seems to hurt them. I'm not sure if other meds had the same effect. My pleco probably wasn't helping, either - always trying to eat algae off the leaves, probably damaging them in the process.