What kind of plant is this?

[nero]

I have exactly this kind of plant, and it is turning yellow as well. Im lighting it for 11 hours a day (40watts) my tank is 24 gallon. I added a once a month fertiliser when i got it about a couple days ago? any help would be great...
thanks

 

[LimpingFish]

Actually
my plant doesnt turn yellow, the lower leaves just stay green and i think they're starting to rot or somthing (they're getting brown stains, and it's not algea)
Plants turning yellow is usually means there's a lack of iron