Round gobies are bottom-dwelling fish that perch on rocks and other substrates. They are aggressive fish and voracious feeders. They will vigorously defend spawning sites in rocky or gravel habitats, thereby restricting access of other less aggressive fish to prime spawning areas. Gobies also have a well-developed sensory system that enhances their ability to detect water movement. This allows them to feed in complete darkness, and gives them another advantage over other fish in the same habitat.
Gobies also are capable of rapid population growth.
They spawn repeatedly during the summer months, and each time, a female can produce up to 5,000 eggs. The males die after spawning. In the United States, studies have revealed that the diet of round gobies includes insect larvae and zebra mussels.