they must be deep I'd imagine
When we fished Candlewood L in Conn. we tried deep water- nothing. As we were coming in to go home we spotted a few anglers closer to shore with weeds up against the ice on the surface in 5' according to line length once the lure hit bottom. Sure enough after we cut holes in weed pockets - panfish, a pickerel and a small bass - over two dozen in 30 minutes as the sun was setting. Wasted the day in deep water.