Minnows work well for rainbow trout. In rivers, streams, ponds and smaller lakes, they are a very popular bait for catching rainbows. On the bigger lakes, most anglers will be trolling in bigger boats and fishing deeper water, so the live bait isn’t really a preferred way to fish for them. For the smaller waters though, try using some of those fathead or shiner minnows in the 2.5 to 3.5 inch range and you should be able to get plenty of action.