My Midas has been raised with other fish since it was a baby and also grew up in a 120g. He is very mellow for a Midas, which I think is doe to the tank size. I think that he may even mellow out more once he gets into his new 210g home. The larger the tank the easier it seems to integrate more aggressive fish.
I can do without EBJDs... but FH??They're my favourites!! I guess if it doesnt work out i could always keep em in a separate tank. Ill try to get a young one and introduce it the tank, like DMD123 said about his Midas.