The male enters the nest, fertilizes the eggs and ventilates them by loosening the top of the nest. The small clusters of eggs are adhesive to one another but not to the nest or substrate. He may even clean the eggs with his mouth. He dismantles the nest as hatching approaches. The clusters that contain individual eggs are crushed in the process and the eggs are scattered, which may give them a greater chance of survival.
Eggs usually hatch within seven days.
Threespines may spawn multiple times during breeding season. Adult threespines usually feed on small crustaceans. In the summer it lives in the Bay's estuarine grass flats and returns to deeper waters in winter. A single male may build and maintain several nests simultaneously, which are similarly constructed of grasses and fibers cemented by their secretions. May. Male fourspines usually have a one-year life span, while females may live to spawn again at the age of two.