Over the years the manufacturers have produced a wide variety of colored floating lines, from dull green to some of the most vivid colors you can imagine. I suspect they do this to catch the eye of the buyer, "this is what's new so I have to have it" type hype. Can't blame them, they stay in business by selling items so why not produce a new line or color? I agree with most of the posts so far, no, the color of the line will not disturb the fish, usually. There are those spooky fish in low clear water that you have to be concerned about, but then any color of line will make them take flight. That is when you start casting upstream and have your line off to the side, think reach cast, and only let the leader and tippet go down the stream in the path of the trout. I use lines of all colors and for me it does not make a difference.

Larry ---sagefisher---