Ahh finicky fish, just when you think you got them figured out.

Ain't this game we play great.

That situation sounds more like a change in tactics not a change in flies. Fish aren't feeding so you have to induce them to feed or at least attack, drastically slowing down or drastically speeding retrieves and presentations up would be two ways to trigger a strike, no so much to feed but to trigger an aggressive response, a just to kill it strike. As I see you have been doing make sure you keep those hooks sticky sharp.

Good luck