Try removing the bully for a week or two in another tank. If you don't have a spare tank you can buy a breeder net to put him in and keep him in the same tank. Some times time outs works and some times it doesn't. I've had more luck keeping the bully isolated for 3-4 weeks. If that doesn't work you will have to get rid of him or else he will keep stressing your tank mates and they will end up developing malawi bloat.