Blackspot sergeants are common in tidepools and rocky shallow areas with moderatesurge at a depth of. Juvenile blackspot sergeants are common in tidepools where they feed on algae, small animals, and plankton. Once they mature and become bigger, they are known to move towards deeper areas with more surge. Blackspot sergeants are very territorially aggressive, especially towards other fish in tidepools. During the day they are often found near rocky areas, although at night they tend to take shelter under various objects. Blackspot sergeants are oviparous and males build a nestsite in rocky areas to attract females. During this mating period they are believed to be especially aggressive.