my tanks 210-240, have 6 large ones in there atm, with some rams and cories, fine imo aslong as filtration is up to it but i am selling 2 of them so 6 is only a temp number. I'd personally say go for 2 males 2 females (weather they pair or not but might keep fighting down, i have more males than females and they fight a fair bit) and some fish which are compatible, thats if your going for big fish you could get a nice shoal of smaller fish then when they get too big sell off the ones you don't want. Good idea would be a good thicket or 2 of tall broad leaf plants for hiding spots.