Stop inappropriate elimination by confining the new cat with diffuser and litterbox, then reintroducing to the resident cat.
J. Veronika Kiklevich, DVM
Q. Our new, formerly stray cat is about 9 months old. He recently started attacking our other cat. Also about a week ago, my brother was playing with our other cat, and the new cat obviously did not approve. He found a convenient corner behind my brother and urinated. Then, the other day he went behind our Christmas tree and urinated. Please explain the peeing issue and the aggression toward my other cat.
A. Neutering your new cat may help his unwanted behavior. Confine the kitten in an area with a feline pheromone diffuser and a litterbox. Also, begin a slow reintroduction of your new cat to your home and current feline resident.