Everyone here is right about asking your tank size. With tank big enough they will ignore one another. I have a flame and it never bothered anything I add because there is enough room to just swim away to diffuse aggression. But in general, you'd hear most people recommend flame to be the LAST fish you add. I would add the snowflakes first, clowns IME are more finicky in new environment where as all the flames I have/had make themselves at home within 2 days regardless of what's in there first before them.