There's little doubt that crayfish are their favorite food. But since crayfish are nocturnal, they're not always readily available. They might feed on crayfish the most at dusk and dawn, two periods when both animals are active. In midday, smallmouths in flowing water may take up a station alongside of rocks to ambush food that drifts past. As the water warms to about 60 degrees in April or May, smallmouths go into spawning mode.
Males take the entire responsibility for nesting and rearing the young.
They build a nest by fanning their tails over small stones or coarse sand. Smallmouths locate their nests by natural features that afford them protection from predators and minimize their energetic cost in raising their young. Their nests are usually in water less than 3 feet deep, and near boulders or submerged logs, with overhead shrubbery. After the nest is built, the male will force ripe females to the nest. When the eggs are fertilized, she is driven away and other females are encouraged to breed.