Any of about six species (genus Micropterus ) of slender freshwater fishes of the sunfish family; found in eastern North America.
Two, the largemouth and smallmouth black basses, have been introduced into other countries and are prized as hard-fighting game fishes. Black basses are larger and longer-bodied than sunfishes and more predatory. The largemouth bass may grow to 32 in. (80 cm) long and weigh 22 lbs (10 kg); it lives in quiet weedy lakes and streams. The smallmouth bass, which usually grows to 5–6 lbs (2–3 kg), inhabits clear, cool lakes and running streams.