How to get my Dwarf Gourami to be nice to other fish?

Fish are like people, if they just dont like something theres no way you can persuade them or teach them to enjoy it. Honestly, I think you should leave this fish in his own tank and let him be because if you've tried this numerous times, then clearly hes not the type of fish to get a long with others. That's never a bad thing though, that mean's hes dependant on himself and likes his own property :P I just think you should leave the fish by itself and hope for the best.