Both armatus and gatf can be fragile at that size, while dorado can be extremely aggressive. You can do it, but be ready for the outcome of them not last very long. Also, from a growth perspective the dorago will grow the fastest, then armatus, and then gatf.
Never kept these guys, just researched them. Took a try at a gatf, but failed. Those that have been successful are experienced keepers that keep dithers, and closely monitor the tank.