I have had a session previously on wahoo where we trolled every type of lure we had, cast every popper, minnow stickbait and even tried bait etc to not avail. There were wahoo everywhere as you could see them just milling around doing nothing and then for some reason, something turned them on. We saw one fish change colour (on the bands on the side of the fish) and within seconds, this happened with every fish we could see. From that point on, you wouldn't have put your hand in the water.
I've also had this happen wth tailor where there was a school of thousands that wouldn't touch a damn thing and then one of them gets turned on by a popper and its on.