Selective fish can frustrate you, but if you are prepared, you can quickly make the change to match what they are eating. In this case, a Rainbow who was eating Trico duns immediately switched to emerging PMD nymphs. How did I know? The rise forms were more hurried as it was chasing the bug from below the surface and turning downward after eating the nymph. What pattern worked for this fish? My PMD Ice Emerger. The wing on the Ice Emerger duplicated the adult crawling out of the nymphal shuck. I'd say it worked pretty good. There were several fish eating these nymphs 10 feet above fish still eating tricos. Always bee on the lookout for easier fish. There is a huge difference between throwing a #22 spinner than a #18 dry and dropper.