A decent liquid aquarium plant fertiliser will make a huge difference to plants. It takes a few doses but once the plants have repaired the damage, they tend to take off and grow really well.
A good way to monitor plant growth is to photograph the tank each week and compare pictures.
Pretty sure the one on the left is needle leaf repens (Ludwigia arcuata). Definitely not Rotala indica...unless it's a different form from what I've kept.