Need more info here. What size tank? What species is the new cichlid? Are you providing lots of places to hide in the tank for them?

excuse me i'am having a problem with a fish i have had for 6 months now its a Zebra Cichlid and just the other day i bought another Cichlid and i put him in the tank and the Zebra Cichlid Attacked it and i had to take the new one out how do i get them to like each other or wat should i do please reply i need help