Lepomis cyanellus, commonly known as the Green Sunfish, is a small freshwater fish native to North American streams, lakes, and ponds. It features a dark olive-green body with a blue-green sheen, and distinctive orange or yellow fin edges. Known for its aggressive feeding behavior, it primarily consumes insects and small crustaceans. The Green Sunfish plays a crucial role in its ecosystem by controlling insect populations and serving as prey for larger fish and birds.

Lepomis cyanellus, commonly known as the Green Sunfish, is native to central and eastern North America. Its natural range extends from the Great Lakes region, including parts of Ontario, Canada, south through the Mississippi River basin and into the Gulf Coast states of the United States. It is also found in the western United States, though some of these populations may be a result of introductions.

The Green Sunfish typically inhabits slow-moving or standing bodies of water such as ponds, lakes, and slow-flowing streams and rivers. It prefers warm, shallow waters with abundant vegetation, which provides cover and feeding opportunities. The species is tolerant of a wide range of environmental conditions, including variations in temperature, oxygen levels, and water clarity.

In its ecological niche, the Green Sunfish is a versatile predator. It feeds on a diverse diet that includes insects, crustaceans, and smaller fish. The species is known for its adaptability, often thriving in environments where other fish might struggle. This adaptability also allows it to outcompete native species in areas where it has been introduced, impacting local ecosystems.