i would like to just say i had a group of dovi (young male about 6"+ 3 slightly smaller ones), they were at ease in a grow on tank that is home to my pair of JD, male is about 7" and he would kick the dovi about when they when near his girl. so two point from this, your top dog might not always be that way when a girl is in the mix and when i moved the dovi into there 180g they all turned on each other for territory even though i left a pair of convict and young in there from cycling the tank, so moving fish will have a difference to behaviour patterns.
i when to my lfs, a fish specialist as i herd they had a few new bits in that were up my ally, so i had a browse and seen the best housing i have seen in years, 3" dovi, maybe 4-5 with 2 other types, one unknown the other EBJD both types smaller than the dovi which had clearly been on the war path. the kicker is the labels on the tank was correct, in that dovi are aggressive and should be housed alone, EBJD are more docile and can be kept with similar size placid fish. some shops cant even read there own labels.
