Hello.

When I approach the pond the Yellow perch come to me and I often seen small perch (fry) swim past them without them touching them, but if I put minnows the same size they chase after them.

Have you ever observed this.

From the research I made they said yes, fish can recognize their own species (sight, smell, chemical signals) and avoid them if there are other species to eat, but this behaviour isn't absolute if there a lack of food cannibalism occurs.
A+