I've found mine to eat anything that floats past his lair. He's not picky at all. He even eats flakes & pellets. The only complaint I have is he likes to use my hermits to add to his lair. He doesn't even care if the shells are empty. He just piles them up. I've lost at least 1/2 a dozen hermits this way. I think he wedges them together so tight they can't move. have you seen yours using shells? I also have a pistol but they are not friends. I heard the pistol snapping a few days ago & went to check it out. I saw him snapping at "spot". Spot was expelling water from his mouth pushing the pistol away. It only took 3 times & the pistol gave up.