My older cat hisses at the new cat. How to make them get along?

This is not uncommon, cats are not naturally sociable and take time to accept new cats into the territory. Pheromone products and calming supplements or diets such as royal canin calm can be very helpful

It may take time for Lilly to accept your other cat even though she is the smaller new cat. Some cats just don't do well together so if this behavior continues or gets worse I would recommend either talking to a veterinary behaviorist (if there is one in your area) or considering finding someone who can provide Lilly a great life as an only cat. Thank you for using Petco Pet Education Center, formerly Petcoach.

The next step is to rotate rooms daily for at least 2-3 days. This allows the new cat explore the rest of the house while the resident cat spends some time in the new cat's room. This will give your resident cats a chance to smell the new cat and rub their own scent on objects. The cats should be fed in each area with wet food twice daily, and it is also good to play with the cats in each area at least twice daily. The practice of setting up a schedule of feeding treats of wet food, as well as a playtime routine, minimizes anxiety and makes the cats feel more secure. Keep the cats in separate areas for as long as it takes to allow them the chance to become desensitized to the smells and sounds of the cats in the other area. When they all seem particularly relaxed with this process, begin to expose them to the sight of each other. A good way to accomplish this visual introduction is to bring the new cat(s) in a carrier to meet your cats and sniff each other through the carrier wire door. Place the carrier on the floor and allow them to meet this way several times a day for about an hour. Continue these meetings for several days or until they remain calm in each other's presence. If and when the cats are able to stay calm in each other's presence during these meetings, it is time to let the new cat out into the rest of the house for a few minutes. The length of the visits can be increased gradually each day. Depending on the personalities of the cats involved, this process may take a few days or a few months. If it appears that any fighting maybe be close to occurring while you are supervising, put the newcomer back in his/her room and proceed more slowly. If those supervised play times go well, you can begin to allow them to cohabitate in your home. If any aggressive behavior occurs at any time, begin the introduction process again. It is very important to understand that this process can take as little as a few days, to sometimes much longer. It is all dependent on the cats involved. If things don’t go well right away... One of the most important steps to dealing aggressive behavior between cats is to recognize the different types of aggression and understand their underlying causes. A short list and description of some commonly seen aggressive behaviors include: chasing; ambushing; hissing; swatting; and/or biting. If you see these behaviors, seek help from your veterinarian. Most cats get along fine if the introductory process is done correctly. Please seek help from your veterinarian if you feel that things are not progressing well, or if you have other questions.

It does take time for the existing cat to get used to a new addition to the house, and I recommend introducing them slowly to each other. Take the kitten, and put her in her own room with her own food, water, and litter box. Keep the door closed, and for a few days, feed them both treats on other side of door so they associate each other's smell with a good experience. Then let the other cat in the kitten's room while the kitten is in a cat carrier. They can smell each other, but not be in contact. If either becomes upset or show signs of aggression, remove the second cat from the room, and try again later. Praise them when they interact appropriately. When they are interacting well with each other through the carrier, you can let the kitten out of her room, and see how she interacts with the other cat. Praise them when they interact appropriately, and separate them with any sign of aggression or upset. I would get a cat tree with lots of shelves to give the cats vertical space to get away from each other. I would keep the kitten in her room when you go out until they are comfortable with each other.

Congrats on your new cat! Yes, I do think that he has the possibility to be happy around the dogs but it will take time. Moving into a new home is stressful for a cat, and getting used to the current occupants is also stressful especially if he hasn't been around dogs before. It's normal behavior to arch and hiss when the dogs come near to Simba, and as long as he isn't reacting aggressively (trying to hit or bite them), then do not discourage this behavior. He is letting them know his boundaries and what he is comfortable with in regards to them. Give him time to adjust and his relationship with the dogs should improve over time :-)

Here is a great article on introducing a new cat to the household. https://www.petcoach.co/article/5-steps-to-introducing-your-cat-to-a-new-feline/ You might want to back up a few steps and try to start the introduction over from the beginning. The second thing you can try is to help Fiona deal with the anxiety of the new kitten by using Feliway, which is a cat pheromone that can be calming. It is available in a diffuser that is plugged into an outlet and is great for a room in the home. It is also available as a spray, which can be used on towels, or the most common locations Fiona likes to spend time. https://www.drsfostersmith.com/product/prod_display.cfm?pcatid=8906 https://www.drsfostersmith.com/product/prod_display.cfm?pcatid=37241 Another product I like is Composure, which is available as a little treat. https://www.petco.com/shop/en/petcostore/product/vetri-science-composure-feline-bite-sized-chews If these do not help, you might consider discussing prescription medication for anxiety with your veterinarian. Thanks for using PetCoach.

Unfortunately it's going to take time. That said, there are a few things you can make sure of to help reduce stress, especially in a four-cat household (which is a lot!). Making sure each cat has their own space where they can eat, drink, play, observe, etc without the other cats bothering them can help reduce territorial disputes over these items. Pheromone collars and plug-ins (Feliway) can also be placed on stressed out individuals, or in shared rooms (since everyone seems to be stressed) to help reduce inter-cat aggression. Making sure to have at least one litter box per cat will also help reduce stress and competition over them, and reduce the chances of accidents elsewhere. Otherwise, continued slow introduction of the cats is best. If anyone starts to get agitated or too excited, removing them to let everyone calm down and settle back in is best. Continued aggression and upset may also need a trainer or veterinary behaviorist's help. That said, if your home is very small, four cats may just be too much for everyone to get comfortable.