My 10 year old cat is vomiting clear liquid...

You should try keeping the dog in one room and the cat in another. They will eventually get used to each other. I wouldn’t force it if I were you. The cat has been there longer so let him have the house while the dog stays in one room. Or, you could take the cat in the room where the crate is kept and just sit next to the locked crate and let the cat sniff around (this worked for my cat and two new dogs).
Good Luck!

my husband the cat expert says that the cat isnt happy with the new situation and you should wait it out

It sounds like kitty is reacting to stress. I agree with @lisaj89, but instead of isolating the cat, you should isolate the new puppy. This dog came into your cat’s home and completely changed his world. Your cat needs the comfort of his own space to deal with the intruder. The puppy should have to adjust to the cat’s home, and should be taught how to treat the cat.

Plus, your cat must eat.

If you know that your cat does not react well to other animals, then why did you just thrust the dog on him? Introducing two animals, especially of different species, is difficult.

Depriving any animal of water is a bad idea.

I have had cats exhibit their displeasure in this way. Cats do not like change and do not like additions to the household, feline or canine. Personally, I would not have attempted this combination unless both were very young and could grow up together. You did not mention how old your cat is, but it sounds like he’s been around for awhile. I think your cat is seriously stressed and you may have a choice to make.

Maybe the cat just wants to be your only one.
I agree with everyone else,
she’s probably overwhelmed and stressed about the new puppy.

@Jeruba One thing about the age, though, is that they often recommend that if you do introduce a new animal with a cat, that you pair it with an older male since you’re the least likely to have behavioral problems.

@Jeruba; I was making a joke apparently not a good one

@J0E, I didn’t flag your answer. But it did not sound to me like a joke, and it was bad advice if taken seriously. Our guidelines ask that we hold off on jokes until some serious answers have been posted.

Yeah, whatever…

@andrew, I never heard that, but if it’s true, I am surprised. Male cats (especially unneutered ones) are so territorial. We did succeed in combining two cat households, but they never got beyond tolerating one another. I would simply not ever ask an older, established cat to endure the addition of a dog and would expect the cat to pine for lost freedom, attention, and a sense of safety and security.

Here you go, @JOE.

Other important etiquette

* If you want to make a joke in an answer, wait until at least one helpful response has been given.

I’m assuming that “Yeah, whatever” means “Thank you for pointing that out to me. I appreciate the importance of guidelines to the community and will try to respect them in the future.”

You’re welcome.

I do respect the rules, but I also have a brain.

From “Cat Owner’s Manual”, Brunner, Dr. David and Stall, Sam, page 68:

“Optimal Feline Combinations: (Fig. A) Two Young, Neutered Males. (Fig. B) Older, Neutered Male with Kitten of Either Sex (Fig. C) Older, Spayed Female with Younger Female”.

Emphasis mine.

I had my Flower (pot) for 8 years. When she was 3 years old we decided to get a little, boy kitten. Everyone said that she would adjust best with a younger boy. Well, she HATED him for about three years. Since then I have added 3 more cats—2 sisters I found in a tree, and a female stray that hung around my old workplace.

Flower and the boy absolutely love each other. My boy cat has two girlfriends, and alternates between loving them and attacking them. But, they all get along just fine. I think it has a lot to do with how you go about the introductions, and you have to allow each pet their own space. Oh, and it helps that I am The Cat Whisperer.

Anyway, just thought I’d say that. So, there. I said it.

When you add a kitten to an older cat, it’s different. Kittens seem to enjoy what we here call “kitten immunity.” The older one typically gives the youngster a lot of leeway by some avuncular or maternal instinct, and there’s also some training and coaching that goes on, such as teaching the young one to groom him or her. That’s all very different from bringing a dog into the house with an older, established cat, don’t you think?

Was that directed at me?

No, @tinyfaery—just a general, conversational “you.” Anyone. Or maybe the questioner. But you do seem to have had pertinent experience, and your comments above suggest that you do think attempting this with a dog is a different matter. That difference seems basic to me.