As said.. In a large tank it is entirely possible, but it comes down to whether the fish get on or not.
I have a couple of girls for my fighter Kokoro. One of them he absolutely despises, the other he simply adores. So if the tank were larger they'd be living together.
This, and have a backup plan such as spare smaller tanks, with heaters & proper filtration as a backup. You may need to separate fish that don't get along. Read posts #27-37 here for some ideas on how to accomplish this.