First thought was a penpoint gunnel, but the white dots and the white head stripe threw me off. And it is a darker green than they usually are. About 6" long, intertidal.
Inside giant barnacle shell in shallow, high-current area.
Caught by fisherman on pier.
Under rock in tide pool.
Juvenile, or Pinpoint Gunnel perhaps? Found by Kevin Hinsta under cobble. Red, with a paler thin stripe from eye to nose, and pale dots running along the lateral line.
Thanks Kevin Hintsa! Nice hand modeling too! :-)