It is also dependent on when they are put in the tank. If they go in together, they're more likely to coexist than if you have one that's already settled in the tank. And, if one is more likely than the other to be aggressive, it's even worse. I'd think that you'd be taking a fair sized gamble. If it were the other way around and the Flasher were in there first, it'd be a bigger likelihood that they'd coexist.