Despite a healthy crop of green hair algae, my lawnmower blenny appears to be starving to death. He looks like a knife blade with a head on the end. I frequently see him working away at the tank walls and there are lots of his little scrape marks on the rock, but I don't ever see him really eating the hair algae, and he doesn't show any interest in nori either. Can anyone recommend something else he'd be likely to eat?