Filas should not be dog aggressive , their jobs require them to work with other dogs. Now with that being said, you can and will see some that are. My Flower is very dog aggressive of dogs not in her home, this started after I had my first surgery after being diagnosed with cancer. She was staying with my friend, where she had stayed many, many times before....when I went out of town, had my son, had surgery, etc. My friend has a female Cane Corso , female Fila who was her best friend, female Rottweiler and a female pug. They were all outside playing and having a great time, like always . I got there to pick her up and went out on the back deck when she heard me she came running up on the deck and was oh so excited. She was sitting in front of me when the other dogs started to come up and she just flipped and started attacking them one by one . It was very scary! From that moment on she will attack any dog that gets near me no matter the size. Now I can bring in a puppy and she will be just fine, she will not cuddle with them or go out of her way for them, but she will not attack them and will eventually play with them . I have added 2 dogs to my pack since she started this, but both came in as puppies.My Maddie loves everybody! I have never had a Fila in my 21yrs with Filas, that was dog aggressive. I have brought in fosters of all ages and sizes with no problems , brought in intact males that I showed with no problems . Until this crazy girl. She is the queen bitch and rules all of the dogs interactions with each other . So, back to the point....they should not be aggressive to other dogs in general. Especially bringing one in as a puppy.