Common fish guide
The following pictures are examples of fish commonly found in streams and creeks in Pennsylvania. Fish shocking is a good way to capture and examine the fish in the watershed.
Sunfish come in many sizes and colors, but basically the same shape. Many common sunfish, such as the Bluegill and Pumpkin seed have brightly colored earflaps beside their gills. Most sunfish inhabit quiet, weedy ponds or mud-bottom streams. Some are also found in rocky bottom streams.
Brook trout like cool, clear waters in lakes and large streams. Normally, these fish are found in more turbulent areas, such as riffles.
The Johnny darter belongs to the perch family of fishes. They are commonly found on the bottom of streams. They settle to the bottom and dart forward occasionally. Darters are extremely sensitive to pollution and will only inhabit clean water.
The above information taken from A Guide to Common Freshwater Animals part of the Environmental Education Leaflet Series #6 published by the Commonwealth of Pennsylvania, Department of Environmental Resources, Office of Resource Management and Bureau of State Parks.
Descriptions of the fish can be found in Reader's Digest North American Wildlife.
The Pennsylvania Fish and Boat Commission hosts an online guide to Pennsylvania Fishes.