There are MANY more neat fish images on their web site. There is a wealth of information on the world wide web on fish and fishing. Take a look at A list of interesting fishing web sites . There are a surprising number of different habitats in a river, many more than in the still waters of lakes or ponds. Water flow depends on the slope of the land.
Younger rivers tend to have steep slopes, fast-moving water and narrow floodplains.
Older, larger rivers carry more sediment, flood larger areas of nearby land, and have only periodic rapids or riffles. Water striders, whirligig beetles and others use the water tension to ride the surface of rivers. Beaver and muskrat burrow into streambanks, while clams and worms hide among rocks and in sandy bottoms. Animals react to the flowing water in a variety of ways. Some have shapes and methods of locomotion that allow them to swim against the current, like the rainbow trout in the River Olympians exhibit.