Delayed Harvest and Stocked Trout Streams: The browns and rainbows in our large trout streams are feeding well on the mayfly nymphs which are very active now. Effective flies now are Mr. Rapidan Bead Head Nymph size 14, Mr. Rapidan Emerger size 14 and Mr. Rapidan Olive Soft Hackle Nymph size 14. Fishing these as a two fly rig is very effective in the deep pools. Excellent streams are Passage Creek, Back Creek and the South Fork of Piney River.