The black prickleback is found from Kodiak Island, Alaska down to northern Baja California. These fish prefer to live in rocky areas with algae cover, mostly in the lower intertidal and shallow subtidal zones. The fish can be found under rocks and in gravel areas, and small ones are common in tidepools. Pricklebacks are capable of breathing air, and can stay out of water for 10-23 hours if they are kept moist by burrowing under seaweed or wet rocks.
Spawning takes places from February to April in the waters off central California, and in late April to mid-May in the cooler waters off British Columbia. Females are oviparous and lay between 700 and 4,000 eggs in nests underneath lower intertidal boulders. The eggs are depositied one by one, fertilized by the male, and then shaped into spherical clusters by both parents. The male guards the egg clusters, and may fertilize - and guard - eggs from more than one female.
The prickleback feeds on crabs, gammerid amphipods, worms and some varieties of algae.