Characteristics - olive colored with brassy reflections and dark mottlings along the sides, whitish breast and belly; 6 spines in anal fin and 12 in the dorsal; they do exceed 10 inches in Manitoba and as such are a trophy. Foods - aquatic insects, minnows and other small fish. Expert's Tip - true to their name, the rock bass can be caught in creeks and small rivers by fishing close to the rocks near the current.
Other names -- redeye bass.
Occurrence of this species occurs in clearer, rockier habitats of small rivers. Rock bass are also found in the rivers eg. the Assiniboine, Little Saskatchewan. Occasionally they are found in large, natural lakes and impoundments such as Lake of the Prairies and Lake Wanapotah..
The rock bass is a stout, heavy-bodied sunfish with a large mouth, which extends beyond mid-eye when the mouth is closed. The spiny dorsal fin and soft dorsal fin are broadly connected but without a notch. The dorsal fin is much longer and more pronounced than the anal fin. Six anal fin spines and 12 dorsal fin spines distinguish this fish from all other sunfishes. Body color is olive with brassy reflections and dark mottlings along the sides. The breast and belly are whitish, and the lower side has spots that form prominent horizontal lines. There is brown mottling and faint banding on the anal, dorsal and tail fins. The pectoral fins are rounded, set low and are amber in color. In more turbid waters the rock bass tends to have a whitish apperance.
This fish can live a wide variety of waters, and their location and food habits are quite similar to the smallmouth bass. The smallmouth, however, are far more piscivorous. Young rock bass consume zooplankton as their primary forage, but as they grow larger in size there is a selection of more aquatic insects in the diet which is supplemented with minnows and other small fish.
The rock bass is mainly a sedentary and secretive fish spending much of its activity passively hiding in the shadows of underwater structures
Spawning occurs in the spring. Nest building by the male starts when the water temperature is 65 to 75 degrees F, usually in late May and June. Nests are constructed by males over gravel and sand bottoms where the females lay several thousand eggs. Females contain an average of 5,000 eggs, but one or several fish may deposit part or all of their eggs in a single nest. After hatching, the young fish are found only in quiet water areas protected from waves and strong current. Rock bass grow 1 1/2 to 2 inches the first year and reach 5 to 7 inches in length after three years. Rock bass have lived 13 years in nature and weighed 1 1/2 pounds. Generally speaking rock bass are in the 6-8 inch range but some rock bass in Manitoba exceed 10 inches.