What Jed said! The other week while pond fishing, I saw a few casts into new water spook a number of fish from their spots right next to the shore in skinny water. Particularly when the presentation was more like heavy ordinance than feather soft and stealthy. I use green, neon yellow, and yellow orange lines and the fish that spooked saw the line and ske-daddled while it was still incoming about a foot and a half above the water. Some fish also spook when you "line" them by over passing them with a retrieve. And on the other hand, some hungry fish will strike the flyline like trying to smash a bug.

An Orvis employee I spoke with last month was switching his 10 wt albie reel to clear line to avoid getting it cut by fish during a blitz.

good presentation, stealthy watercraft, sufficient leader/tippet length should allow you to use "psychedelic" line if you so choose......IMO and 2 cents. HTH.

Steve