When I've done it they were the boss of the tank but weren't a problem. A benevolent boss in some tanks is a good thing, keeps order in the tank. All in all I'd say they're a sometimes it works, sometimes not proposition. Depends on the usual factors, tank size, tankmates, individual fish.
For me personally, rivulatus have never been a problem with one exception-- wilds I've had that were quite aggressive even at 2".