Markings on sword plant

[Fishies86]

Hi, can anyone tell me what these markings are on my sword plant? Is it normal? Also, does anyone have any idea why the leaves are now growing long and narrow? They were quite rounded when I got them. I've got a 48l (10 uk gallons) tank with two 15w daylight bulbs if this is any help
Thanks in advance

 

[fort384]

Not sure what you mean by markings. The leaves are probably growing more slender because of a change in light or other nutrients.

 

[Fishies86]

Not sure what you mean by markings. The leaves are probably growing more slender because of a change in light or other nutrients.

Sorry, I wasn't very specific was I? the leaf on the left, and most of the new leaves have got black horizontal lines on them. I know it's not a great pic, but it's the best I can get with an iPhone camera.
Is that normal, the leaves growing like that? Or is it a problem that needs fixing?
Thanks for your reply

 

[fort384]

As long as the leaves are green and not prematurely dying it's fine. the markings just look like leaf structure to me, if that is what you are talking about.