If you have more than 1 dog, they need to learn to live together. For some yes it comes naturally for others they have issues.
It is important they are introduced to each other properly at the start.
If an issue comes up later then you need help, they rarely just sort it out.
Understanding what is happening and how to change it is vital.
Of course you need support through it too.
email me firstname.lastname@example.org if you need help.