Now, I'm no plant expert, but I have affection for red lilies, like the one you have. IME, they need a good substrate and HIGH light. Red plants, as a general rule, require more light and nutrients than MOST "green" plants. I have a ten gallon with 3 lily bulbs (one red tiger, but I don't know the others) and 2 babies. My bulbs have been producing good results. I have an iron rich substrate with black sand over it to keep it out of the water column. I also have 2x 20" lights with plant lights over it, to give it good, bright light. I put dupla drops and flourish in every day, according to directions, and some other fertilizer in every 2-3 days. I also have yeast powered CO2 going into the tank with a ladder diffuser. I have had a lot of good growth from my Ozelot sword, the 3 lily bulbs and several other "reddish" plants.
I just love red plants; in fact, I love red in the aquarium, period. I have 3 adult cherry red shrimp, with at least 6 babies, 10 young Cardinal tetras, 3 botia striata, and 2 khuli loaches, and WAY too many snails.