If two cats are always fighting when they are together, you can take the following measures:
1. First, separate the two cats to reduce direct contact and allow them to gradually get used to each other's presence.
2: Ensure that each cat has its own food, water, and litter box to avoid competition for resources.
3. After a period of isolation, the two cats can be gradually allowed to observe each other through transparent partitions or other means to gradually increase their opportunities for contact.
4. If your cat is not spayed or neutered, consider having the surgery done, as this can help reduce aggressive behavior.
5. Feline pheromones can be used to relieve cats' anxiety and promote peaceful coexistence.
