When someone is planning for fish it is necessary to choose right destination /rivers. There are mainly three rivers as already explained in above posts viz. Freestone rivers, Tailwater rivers and Spring creek rivers.
In the Freestone rivers or streams, the main water is the surface water that is water flow mainly from snowmelt and rainfall. Hence, they rise and fall of water are basically based on the seasonal fluctuation. In summer season, due to rise in temperature snow melts and river swell with water. But due to continuous rising in temperature the flow ebbs back throughout the summer. Then it reaches to its lowest level. In summer season, the water level becomes low and in this less flowing muddy heavy water more insect population grows hence there are more and healthy fish population. Freestone water body may vary in size from small stream to large river. Freestone river or stream displaces stones while flowing through the river or stream bed hence, it is called as freestone. These rivers are not impeded by the construction of a dam.
While tailwater rivers are created from the flow of a reservoir of a dam and essentially has dam. Fishes are present in the down streams of rivers at the bottom of dam due to rich nutrient in the sediments. Tailwater may have some very large fishes due to high nutrient availability. In tailwater river flow can be lower or higher but these rivers do not have muddy water. Tailwater fishes mainly feeds on caddisflies and mayflies.