This creature is one of the most common stream fishes in Pennsylvania. Because they are often natural prey for predator fish, they are commonly used as bait. Averaging 4 inches, this fish is light to dark olive, with a silvery shading on the sides and purple-violet reflections above a silvery belly. Males build nest by pushing pebbles, building a row of gravel in line with the flow of the stream which has a depression at the end.
Males vigorously defend the nest against predators.
Since many schools are involved right now with a lot of macroinvertebrate work, identifying this feature creature should be a breeze. This creature is a true fly . Adults can be easily recognized, but the larvae are a little harder to identify. The larvae have fleshy, segmented bodies and a well-developed head that is partially or fully retracted within the thoracic segment. The last abdominal segment has two obvious spiracles or breathing holes that are bordered by one to six finger-like lobes.