"coho buggers" tied on sizes 4,6,8 with a chartreuse green always have done VERY well for me in low light conditions (early morning/late evening). for some reason, while fishing both campbell and Nile, the fish would not be grabbing the person (who i was fishing with) pink fly, but as soon as he changed to the green, he started catching fish. my guess i it has something to do with visibility... because Mid day the pink flys usually out produced. had cutties hit it too
now before anyone starts to get up in arms about fish biting in the river/pre-spawn... it was just an observation. no the fish were not flossed!