HELP PLEASE! Is this normal?

It can be normal. Some cats take a while to get used to each other, even if they're related. Cats of any type are not as social as dogs are, and, if left in the wild, most cats are solitary. Female cats aren't used to having their young around once they've been weaned and are old enough to be on their own.

If they aren't fixed, that would be your first step. Cats in heat are irritable anyway, and it's a good thing to do from a health point of view. This may calm both of them down enough so that they won't fight.

Time may help things out as well. They may be establishing who's the boss and just need time to work it out.

If that doesn't help, you can get something called FeliaWay. It's a pheromone that you can get as a plug in that may help. The only drawback is that you have to have one in each room the cats have access to. If they'll wear bandanas, you can also get it in a spray and apply it to the bandanas as needed.

If all else fails, you may have to put one (or both) on anti-anxiety medication. It's cheap and doesn't have many side effects, but giving cats medication on a twice a day basis isn't really fun for anyone involved. I would try the other things first, but this is always an option.

Hope this helps and I hope your cats get to where they get along. It can be frustrating to an owner because cats don't have clear cut social structure like dogs do.

It's normal and is common in female cats, particularly if they are not spayed. Female cats are quite territorial but they calm down somewhat when they are spayed. However, in some cases, female cats that don't get along will result in one of them running away. I had a female cat that didn't like our other female cats and one night, she got outside and left for good. This really shocked me because she had never shown any indication she would do this. When she was outside during the day, she stayed in the yard and I didn't let her out at night. I did notice that she interacted very little with the other cats and largely stayed away from them. I didn't realize that it was because they didn't like each other. I always assumed it was cats that kept fighting with each other that didn't get along.

It is normal. They are fighting for territory. Takes them a while to make boundaries for each other. Some ways to calm them down is to give them catnip or to train them. By training them i mean like when they attack each other show some discipline to show its bad. I used to own 6 cats of my own and they fought all the time! Two were sisters and they don't even like to be within 10 feet of each other. Just give it time.

Cats are solitary creatures and territorial. Females tend to be worse. A male and female or two neutered males tend to get along better.