Mike, I have 5 small PS's in a 35 gallon tank. they were brought in from the pond in early nov. At first I fed them some aquamax that I had ,but they didn't show much interest. Then I gave them Tetrafin goldfish flakes and after a few days they were more aggressive in their feeding. Now when I go to feed them I hold the food can over the tank and they follow it where ever I move it.
They will peck at the aquamax when I put some in, but they go crazy when I feed them the goldfish flakes.
It could be that the flakes are easier to eat than the pellets cause their only 2 to 3 inches long.
NANFA Dave mentioned the NCRAC. site, there's also another site NANFA. if you join their forum those guys have lots of experience keeping game fish in aquariums.