Pedro, try feeding it temporarily nori... soak it pretty good so it's soft. The same stuff you would feed tangs. I used to do that when I had a couple of them in my old 100 gals when nuisance algae weren't abundant
Those guys would demolish Hair Algae and other type nuisance algae in my previous tanks. Just make sure your vortech's and other strong pumps are covered so they don't get sucked in and get blenderized.