These nonnative trout, introduced in the U.S. in 1883, have a reputation for being wily and elusive. While they prefer cold spring-fed rivers and streams, and lakes with cold water inlets, brown trout also can be more tolerant of warmer streams and lakes. These trout can range in size from 11-inches long in small streams up to 30 inches in larger rivers and lakes. While brown trout have a varied diet, anglers targeting large brown trout often use spinners or flies that mimic minnows.