Early Brown Stone. A fly for opening season is guaranteed to be the Early Brown Stone fly, especially in the month of March. This fly is the number one prey for trout and salmon this early on and it is a fly that is sadly neglected for the caddis or the Mayfly, no doubt these flies are fantastic but the Early Brown Stone Fly takes the top of the charts in the earlier months in the year hands down. Fishing this fly from the morning up until midday is the most effective window for productivity.