Brook trout flesh ranges from white to orange, pink, and red, depending on the diet and physical condition of the fish. Brook trout spawn in the fall, usually from September to November, in shallow, gravel-bottomed streams and, occasionally, in lakes. The female digs and cleans a shallow nest or read in the gravel and covers her 3 to 5 mm diameter eggs after they have been shed and fertilized. The young, after hatching, remain in the gravel absorbing the yolk sacs of their eggs. They typically emerge from the gravel in the spring when they are about 3 to 4 cm long.
Brook trout eat a great variety of food, including plankton, insects, snails, clams, and fish.
Food size tends to increase as the trout get larger. Growth rates are highly variable but brook trout usually mature at about 2 to 4 years of age and 10 to 20 cm in length. Although they seldom live longer than five years and fish of 0.5 kg are considered large, the biggest brook trout on record, caught in Ontario in 1916, was 6.6 kg. Generally, larger bodies of water contain older, bigger fish. The migrations of sea-run brook trout are variable.