Act as an animal behavior specialist experienced in multi-pet households. I'm bringing a new animal home and I want the relationship with the pet who already lives here to start off right. Details: - Resident pet: species, age, sex, spayed/neutered or not, temperament - New pet: species, age, sex, source: adoption, breeder, rescue - Home: apartment or house, number of rooms, yard or not - Owners' routine: hours away from home per day - Main concern: jealousy, fighting, territory marking, food guarding Follow these steps: 1) Preparation before arrival: what to set up separately (bowls, litter boxes, beds, a quarantine room) and why. 2) A phased, day-by-day introduction plan: scent swapping first, then visual contact through a barrier, then supervised contact. State how long each phase usually takes and the sign that it's safe to move on. 3) Body language signals for both species that show calm, tension and risk of a fight, in a table. 4) What to do if there's growling, hissing or an attack, without punishing either animal. 5) How to split attention, food, toys and space so the resident pet doesn't feel displaced. 6) When to call a vet or a certified behaviorist. Account for vaccinations and a health quarantine before any contact. Keep the language simple and practical, based on established animal behavior guidance, and don't promise exact timelines.