I don't know if YP will eat a 3" smallie, but they love bluegill up to 1.5".
from
DYNAMICS OF A BLUEGILL, WALLEYE,
AND YELLOW PERCH COMMUNITY
by James C. Schneider
YELLOW PERCH. In the fall diet, zooplankton
was important only to perch <75 mm TL, and
benthos only to perch <127 mm.
Diet of large perch consisted almost entirely of
small perch and bluegill. In the spring diet,
benthos was the only food up to about 203 mm
TL, then small perch became prominent. Bluegill were not found in perch stomachs
during spring. A perch as small as 78 mm had
eaten a bluegill, a remarkable feat as the bluegill was about 27 mm TL when ingested. The longest bluegill eaten was 84 mm, also
relatively large compared to the estimated gape
of the perch mouth. The cannibalized perch
found in perch stomachs were all YOY size.
You better make that 3" bluegill