4 months ago I introduced my cat Miles into my home. I only had my other cat Merlin at the time. Merlin threw an absolute fit and hated him but seemed to get over it for the most part after a month.. BUT his personality has now altered a bit. He doesn't like to be picked up and cuddled as much, and he hisses at me randomly sometimes especially if I have just finished petting Miles. I feel like maybe I should take him to the vet in case this isn't just because Miles is around.. but otherwise he acts normal, likes to play.. eats a lot, etc. Additional info: Merlin is 4, neutered.. Miles is 8 months old, not neutered yet. Help?