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Sunfish, bass, and crappies are spiny-rayed fishes that have their spinous and soft-rayed portions united into a single dorsal fin. The largemouth bass and to a lesser extent the smallmouth bass, however, show a substantial division of the dorsal fin. Sunfish and bass are green and sometimes orange, colorful, fishes lacking an opercular spine; these features separate them from the white bass and their relatives, which are silver or yellow, often with thin horizontal lines. Another spiny-rayed fish in the Great Lakes fauna, the freshwater sheepshead, has two parts of the dorsal fin continuous, but it is distinguished by the extension of the lateral line across the tail fin. Sunfish scales are weakly to moderately ctenoid, rarely cycloid. A single individual of some kinds may exhibit both scale types on different parts of the body. In the Great Lakes, these fishes inhabit all kinds of waters. They are spring spawners over shallow nests excavated by the males. Spawning of some kinds extends into the summer. The males guard the eggs and larvae, and herd the young in some species. The smallest young feed on microscopic organisms, and later, upon aquatic invertebrates. Larger individuals, particularly of the basses and crappies, are chiefly piscivorous. Rate of growth and sizes attained depend on temperature and the amount of food available. Sunfishes become stunted when their populations are too large for the food supply. The usual adult sizes vary among the different species.
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