I know they are film eaters.. But I've never seen any fish not take a look at something live... How about trying some live white or black worms? I got some blenny s eating once with black worms.. Those worms wiggle something fierce once they hit saltwater.. Might attract his attention and get a feeding response? Worth a try i would say.
I do have brine shrimp eggs. Worth a shot?
__________________
You wouldn't want to see my tank. I don't use fancy equipment and I am a noob