 The tidepool sculpin grows to a length of about and has a large head, tapering body, and spiny fins.It has a single pre-opercular spine and tufts of cirri on the top of the head but not on the body below the dorsal fin as the fluffy sculpin ("Oligocottus snyderi") does.It varies considerably in colour, is often marbled in grey, brown and white, but may be reddish or greenish and can change colour rapidly so as to camouflage itself.