I love to have my clients twitch their hoppers to elicit some explosive strikes from the trout. How much do you move your hopper? It depends. In fast moving riffle water I leave them alone as the trout will have a hard enough time tracking a fast moving fly. But in the slower water I start by twitching my rod to move my hopper about 4-6 inches. I pause and let it rest and after about 5-8 seconds I twitch it again. Waiting and then again. After trying this for a little bit and I don’t get any response, I begin twitching faster.
Just like fishing streamers, you have to figure out what the trout want. Do they want the slow retrieve? Medium retrieve? Or do they want it moving fast? Sometimes they really want that hopper moving. But, you need to pause so that the fish can attack. You will miss a lot of fish if you don’t give the trout a chance to catch its prey. Give this a try on rivers that get some pressure and you will stick out from the crowd in a good way.