Ground up feed, even powder sized. Some soak it in water to make it easier. With lots of fish in the pond, the best thing you can do for them is give them protection and a quiet/safe place to eat & breed. My minnows are quite happy to eat feed primarily for larger fish. I take extra for them up to the top end shallows where big fish don't go much. Truly, minnows eat stuff that will be in the water already. They don't NEED feed, but it will help growth.