Delatite River

The road from Mansfield to Mount Buller crosses the river at Merrijig, and from here you'll find idyllic fly fishing water all the way up into the headwaters at the base of Mount Buller. The water downstream of Merrijig also holds trout through to Lake Eildon, however, willows can be an annoyance, followed by a complete lack of riparian vegetation meaning the water can warm significantly during warm weather.
There are regular access points all along the road to Mount Buller, just keep your eye out for picnic spots, roadside stops and side rd bridges for indications of likely access.
There is also a walking trail that follows the river from Carters Mill picnic area through the Mount Buller resort entry and then on up into the headwater regions of the river.