A healthy stream is a highly diversified ecosystem. Its complex food chain ranges from microscopic diatoms and algae to large fish, birds and mammals according to the Oregon Department of Fish & Wildlife. The diversity of species, particularly aquatic organisms, and their numbers are vital pieces of the stream life for they are the indicators of water quality in the stream as well as the source of various food chains, including fish. A wide variety of organisms inhabit water.

Particularly Fish population play a crucial role in the aquatic food chain as they get their food supply from different sources. The quantity of food availability within the stream is determined by the physical and biological conditions of the area. As long as producers are huge, consumers boost as well. According to the Oregon Department of Fish & Wildlife, Diatoms coating a rock feed primary consumers such as mayflies. They, in turn, feed higher order consumers like stoneflies and fish.

Have you ever try faking a cough, a fever, head ache or a stomach ache with the attention of taking a vacation from school? Huh, I bet your mom knew that you were really sick or just faking, and then let you stay home for the day on purpose. The cough, fever, head ache or stomach ache are indicators that something is not working well in your body. Streams get sick as well. Poor land use practices and pollution in a stream's watershed can cause a poor stream health.

Aquatic organisms, including fish population, have a relatively narrow temperature range for survival. Shade provided by trees and other plants that grow beside the stream helps keep the water cool and within that acceptable range. Insects that feed on the leaves and branches of these stream side plants sometimes fall into the water providing food for the fish.

By closing, in which way do you think a house can be shaped into a dwelling? A house is just the walls, the floor and the roof. But to make it a dwelling, you have to arrange the furniture and hang the pictures, put in chairs, sofas, tables, beds, and your favorite portraits make the house more comfortable and livable. Fishes need homes as well. A stream without structures like rocks, plants, logs, boulders, and gravel is just a house. But with those features in the stream fish can live there comfortably.