They look like minnows to me. Swim/school like half grown minnows.
I've got shinners and perch but they haven't spawned yet...new pond.

I get minnow fry "blooms" where there are football sized clouds of them all along the shoreline, this time of year I have the clouds and out in deeper water minnows from grain of rice size to 3/4 of an inch...bazillions of them.
When I feed it's a free for all...my perch dart right up and back down to get at the feed (although I would think they would be stuffed full of little minnows).

[Linked Image from i.imgur.com]