I adopted a 7 month old kitten (Zeke) a couple weeks ago and kept him apart from my 1 year old cat (Toby) for a week. I did a slow introduction over that time, letting them see each other only through seperate cages, smell each other's scents on towels, going in each other's rooms when the other wasn't there, etc. The intro went fairly well. No growling or hissing at all. Now, sometimes they seem fine together, but other times they both start little fights with each other, going up to each other and putting their arms around the other's neck which ends with them wrestling in a circle on the floor, biting each other. I break it up, since I never leave them alone together. Zeke seems to do this very playfully, but Toby takes this as an attack and I'm really worried he's going to seriously hurt Zeke. He already bit Zeke's face over the weekend and left two little cuts. Toby's about 12lbs and strong, and Zeke only 7lbs and very thin. Individually, they're both the sweetest, gentle cats. Neither of them have ever hissed or growled in their life. Toby seems very jealous and depressed since I got Zeke. He's not as playful and looks hurt if he sees me holding Zeke or playing with him. Does this sound like a normal adjustment period of them getting to know each other or should I worry they'll never be safe to be alone together? I can't even leave them alone if I leave the room, because I'm afraid they'll get in a fight and Zeke will get hurt. Any advice is appreciated.