Liberty Lake opens for fishing March 1st and is open through October 31st. During the month of March fishing can be outstanding for brown trout.. Brown trout are notoriously difficult to catch but just after ice-out there is a window of opportunity to catch them easily at this lake. Once the water warms largemouth and smallmouth bass, yellow perch, and other warmwater species dominate the fishery. This lake also has one of the best brown bullhead fisheries in the Spokane area.