Dianne... have you tried refocusing his mean streaks with a toy that he likes? It works a treat with Pilo when he starts getting nasty! Pilo likes those little balls with a bell inside them that he can pick up and throw to the ground ( with me picking it up of course and giving it back to him). Even a metal spoon is good as he can bite that as well!
Sorry to see you having such a hard time with Blu!
Sorry to see you having such a hard time with Blu!