[Biashpainabix]

PLEASE HELP!
My 5yr old neutered pitty is becoming very dog aggressive, this is new behavior! He has been well trained and socialized, loved cared for, etc. He gets along great with his housemate and my cats. But God forbid he encounters a strange dog. He fixates on that dog and wants (for lack of a better word) wants to kill, he wont listen to me and i have to go to an extreem to get his attention. Im afraid he will turn on his housemate who is oblivious to his aggression and just wants to play!!! I need advise before something terrible happens.

A deeply worried mom,
Luv2Pits