Mine's never touched any algae that I can tell. He takes nips on the LR, I'm not sure what he's going after. He also prefers to lick the glass (you'll see little lip prints on the front and back glass).
Over 3 months, he's acclimated to eating about anything I feed the tank - flakes, pellets, algae wafers, etc. He's doubled in size and looks nice and FAT!
A very interesting fish to watch.