The Rock Bass (Ambloplites rupestris) is a small, robust fish found in freshwater lakes and rivers across North America. They typically grow up to 10 inches in length and have a dark, m... The Rock Bass (Ambloplites rupestris) is a small, robust fish found in freshwater lakes and rivers across North America. They typically grow up to 10 inches in length and have a dark, mottled body with red eyes. Rock Bass prefer rocky and vegetated habitats where they feed on insects, small fish, and crustaceans. Despite their size, they are known for their aggressive behavior and are a popular catch among young and novice anglers.Click here to read more about Rock Bass.