I've read about a variation on the Peter Ross where the fellow mixed in some orange with the red, and found these very effective when there were alevin stage fish fry about (still with the egg sack). I've tied a few up, but haven't noticed them to be any more effective than a standard tie. Mind you, I've not really done the fair test as I should be using them when the fry are just emerging from the nests. If I had the luxury to plan my trips with such things in mind I might do so, however, for now I use them when they shout "pick me" louder than the other flies in my box!

-Jeff