Gotta remember if fish started only eating one thing (like crickets) they would starve to death. the fish are obviously eating other things so what you need to do is experiment around. go back and forth between natural colors and bright ones. i can tell you from personal experience my absolute favorite bluegill fly is a short fat yellow chenille spider with a deer hair wing. yellow seems to be my all time most effective color for bluegill here, but if your only success is on live crickets, try flies that are the same color as those.

and the most important thing, fish SLOW and with a very slow sinking fly. LOOOONNNGGGGG pauses are the only way to bring in stubborn summer panfish