....I set up a 55 gallon corner tank for my mantis awhile back cuz he's like over 5 inches long, a peacock smasher. There's two damsels that made it and a very small clown, about 1 1/2 inches. He used to seem to try to attack the damsels when he was getting used to the tank, but the clown fish is like his lil buddy. There's a pretty good circular current in the tank due to the setup and type of tank and he just loves watching that lil clown fish do his mesmerizing lil swim move he does, he swims right in front of the Mantis and the Mantis just kinda trips on him, I was worried at first but it's been a few months, they get along great.