[4] It is found in the eastern Pacific Ocean from Alaska to Carmel Bay, California down to depths of 18 metres.

Males can reach a maximum total length of 8.9 centimetres.

[3] The species epithet "swanii" refers to James G. Swan of Port Townsend, Washington.

[3] The rockhead spawns nearshore, during the months of January–May in the California Current region.

[5] Its diet consists of benthic shrimp and crabs.