This is a lovely plant. It can be very full like a feather boa. The photo shows a young stem. This was growing from the bottom of my plants and came out much brighter green and less frilly than the larger stems.
These plants need good lighting. Bottom leaves are likely to die off due to lack of light from top leaf shading. Try to make sure they get as much light as possible. The fine leaves also seem to be a prime place for hair algae attacks. Keep the leaves free from algae or mosses which will block light.