Java fern turning black

[gumball]

Hi guys, I noticed my java fern is turning black. Any idea what's up with it? Currently using co2, light is on 11 hours a day.
uploadfromtaptalk1404650702262.jpguploadfromtaptalk1404650715977.jpg

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[diazman]

Looks like the emerse version of the leaf. How is the rest of the plant fairing? IMO, 11 hours is abit high for this low light plant. I would cut back to 8-9 hours for tanks that contain low light plants though, just my 2 cents.