Advice needed please.. rescued 12 month old Female Rottie – growling & today showed teeth when meeting new people

Hi,i just adopted a 12 month old rottie ,he is a sweet boy but lots of work ,he is still a puppy but also so active,i don’t think he ever lived inside because he messes on the floor a lot ,i clean it tell him (no)and put him out,He is joined at my hip ,just wants to be with me all the time ,i have a 11 year labb who is a sweet girl but really don’t care for him ,i did have a recue rottie and he was 3 ,such a old soul he was ans os so good ,never had a problem with him and he was junk yard boy at 160 lbs ,i had him six years and then he got very sick ,he had kidney failure and he couldn’t fight off any infections ,i had to let my beautiful boy go,i still miss that boy ,so i decited i wanted another rottie ,what did i get my self into ,i’ve only had him 2 days and i’m beyond stressed,can someone help me with the potty training at 12 months old ,i’m trying but i guess i;m more stressed the he is ,thanks,Janice

We, too, have an approximately 12-month old female that we rescued about 2 months ago. With one son living on his own and one that was away at college at the time, we took her everywhere to ensure we socialized her. We know that she was abused, and was actually removed from her previous owner. She was fine with people at the beginning. A little shy but would eventually let them pet her. After having her about 2 1/2 weeks it was as if someone flipped a switch. She started to show signs of aggression toward strangers, including towards our sons. We are currently working with a behavior modification trainer. After coming to our home and observing the dog for an hour and half, she believes she has fear aggression. She said it is normal for it to show up two to three weeks as the dog becomes comfortable in her new environment. We did go through obedience training with our dog, and the behavior trainer is showing us how to use what she learned in obedience training to help modify her behavior. If you haven’t contacted a professional yet, I recommend it.

Thank you both so much for your replies and advice. I have sort professional advice. And i have been re training her on lots of different things. At the moment i am telling anyone that comes into the house to complete ignore both dogs just so she feels secure enough that they are not infact a threat. Whilst both dogs are told to get onto their beds.
This is working brilliant and with lots of praise am love she will be fine.
She is such a loving little girl and has come along way in just the past week.
I will keep you all updated on her progress.

Once again. Thank you for your help.

Best wishes.

She has learned this behaviour in her life before being adopted. Whoever had her must have encouraged this behaviour or she got a reaction from doing it to people and was never corrected. Since she is only 12 months old she can be cured. You will need to socialize her as much as you can. Whenever she shows signs of some sort of aggression you must correct her. I use the sound Ahh Ahh in a growl way, as the word NO does not always work. Work with her being on a lead whenever you expect anyone coming over. This way you have more control if the situation arises. Check chain her quickly and firmly before it even happens. Dogs show signs before they do any growling. Like for instants they stay completely still and start to lick their lips. She is not a confident dog and that’s where you are needed to guide her. Best of luck!