I DON'T KNOW WHY
With my Polaroid glasses I could clearly see the trout holding at the end of a bed of aquatic weeds. It was not a remarkable trout for that particular stream; a brown trout probably about fourteen inches long. Occasionally it would tip up and appear to take something from the surface and then drop back down into its holding position. Looking up and downstream I did not see any other fish working so I thought I would take a shot at this seemingly easy fish. An hour or so later the trout was still there, still tipping up and eating something but I never did figure out exactly what.
First I tried a fly that I had been using to imitate the hatch that had been occurring on this stream for the last few days. I presented the fly from several different positions but the fish never budged from its holding place. As I stopped to consider this situation the trout calmly rose up and appeared to eat something from the surface. I walked downstream and waded out into the current line where the trout was feeding and stared at the surface for several minutes but I did not see anything. As I stood watching the water I saw the trout tip up several times and apparently take something off the surface. Now I was truly intrigued.
I retrieved my small insect net from my vest and held it in the water. After several minutes I took it out of the water and checked to see what insects I might have caught. There were some small bits of weed, and small black beetle, a few empty midge shucks and nothing else. There was nothing definitive in the net catches so perhaps the trout was opportunistically feeding; time to experiment.
I decided to try a two fly cast; a small beetle and a small midge pupa on a short dropper tied off the hook bend. Once again I made a number of casts from a variety of different positions and the trout simply ignored my flies and continued to rise. I lengthened the dropper, changed the midge pupa, changed the pupa to a small midge emerger fished just below the surface film and still nothing. I tried an ant, a small flush floating spinner, a dry midge and still nothing. Then, after making a monkey out of me for over an hour the trout slowly moved up into the weed bed and disappeared.
A fourteen inch brown trout had thumbed his nose at my best effort. What was he eating, why did he not at least make a pass at one of my flies, I don't have a clue. I moved downstream a short distance and found another fish feeding sporadically and took him after just a few casts with the same beetle and midge combo that the picky brown trout had refused to even give a second look. Why, I don't have a clue.
A week later I came back to the same spot and there was a trout holding in the same place. It looked like the same fish and I decided to give him a couple casts. The fly that I had on my tippet was one of the same flies that this trout had ignored just a week ago but when I dropped the fly in his feeding lane and he immediately rose and sipped it in without hesitation. As I slipped the small barbless hook out of the corner of his mouth I patted him on the head and slid him back into the water. With a flick of his tail he was gone back into his weed bed.