Yes. This is normal. It can take a few days or it can even take a month for them to start liking each other.
There is a great homeopathic remedy that we use that eases anxiety in situations like this. It's called homeopet (www.homeopet.com) and it works wonderfully.
With time, some of the aggression will ease and your home will become peaceful again.
Let me know if you still have questions.
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