for freshwater minnows i've always had good luck with the end pieces of french bread for the bakery because the hard outer shell holds up well when wet . but truth be told almost anything will work . minnows are like shore line scavengers .
Try a can of tuna, punch a couple of holes in it. I didn't beleive it worked, but a guy fishing a pot next to mine caught a couple of pints, I only got 7 with bread.