From LiveAquaria.com I got: "The diet of the Canary Blenny should consist of finely chopped crustacean flesh, mysid and vitamin-enriched brine shrimp as well as frozen herbivore preparations"
All the lawnmower/herbivore type blennys I have had have eaten right away. My Midas Blenny didn't eat for a couple days. I would feed mysis on your regular feeding schedule, hope he is eating some algae, and try to make sure he isn't stressed.
Good luck!
Mike