Beginner Gardening: Need help with a sparse-looking Pachira Aquatica plant , 1 by pruant

pruant wrote:
Hi, I'm attaching another picture of a leaf (the only big one on the plant right now) that has started to turned brown. This is a relatively new leaf, and is not as brown as the older leaves (that I cut away) that were a darker brown. These brown leaves would also fall off by themselves. Another thing I noticed is that the leaves/stems are very delicate. They break away with the slightest touch. Appreciate any advice. Thanks.