plants for a 75 gal african cichlid tank?

i like the way the plants look in my tank, but it looks like they are decaying? which i don't get because i have a florescent light for the tank. do they need like something else to keep them alive?
 
i like the way the plants look in my tank, but it looks like they are decaying? which i don't get because i have a florescent light for the tank. do they need like something else to keep them alive?
What plants are these? Provide pictures and more details please. Did you get them in good conditions?
 
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