There's still the original three males and an additional one female. Finding more septemradiatus females has proven to be a bit tricky...
One of the males is actually digging a sort of a "nestpit" kind of thingy under the foliage of the Samolus, but the female seems to have no interest in him...
I dunno if there's something I can actively accomplish in order to "start a breeding colony", but I wouldn't mind if they did it on their own.