<human>: Provide a brief overview of the text.

Around a year ago my dog of almost 15 years had to be put down due to some major medical issues.  We are doing a bit better and about five to six months ago decided to get a new dog.  We got a new puppy and my older cat is *terrified* of the puppy.  It can't be in the same room as the puppy without being on a counter or something.  The puppy is not violent in the slightest and gets along with my little cat just fine.  The little cat and the puppy will take naps with each other and just be very pleasant to each other, if not exactly 100% buddy-buddy.

What concerns me is that my little cat and my older cat have been fighting a bit more recently.  At first it seems like they are trying to play, but then it turns violent with hissing and yowling and such.  The two cats used to be best friends, always hanging out with each other, now they just seem to hate each other.  This started occurring since my dog was put down.  It has escalated since the new puppy came home.

I'm not exactly sure what a good solution is for this situation.  I've tried spraying them with some water when they start fighting, which breaks it up for a time, but then they're back at it.  I don't think they're to the point where they're a threat to one another, but they're certainly no longer friends.

My younger cat was a rescue, my older cat was picked up from a litter from a friend of the family, both are spayed and both are female.
<bot>: My cats have started fighting since my dog was put down, used to be best friends now seem to hate each other.