This weekend I will be purchasing the next round of tankmates for my 30 long. I'm leaning towards 3 or 4 the American Flagfish.
I currently have 7 Danios (longfin type) and 6 white fin tetra.
Would they be an appropriate choice?
Any advice? Does sex matter or ratio of male to female?
Things to look out for etc?
You could possibly do so. As the American Flagfish are a type of Killifish, I would recommend doing 1 male, 3 females (this will spread out the aggression from the male to the females).