A stonefly is an aquatic insect belonging to the order Plecoptera. They are typically found in clean, cold freshwater environments, such as rivers and streams. Stoneflies have a distinct life cycle that includes an egg, nymph, and adult stage. The nymphs are important indicators of water quality, as they are sensitive to pollution. Stoneflies are characterized by their elongated bodies and two pairs of wings. They primarily feed on decaying plant material and algae. Adult stoneflies emerge from the water to mate and lay eggs, often during the spring and summer months. Their presence is crucial for maintaining healthy aquatic ecosystems.