Males do have more green in their fins from what I've seen, body color seems to depend on light and mood. I've seen individuals of both genders get blue/purple in their scales in the right light. Might be different if you've raised enough of them but it's easier to tell apart as adults imo (to be captain obvious), when size, color, fins, and head shape are more distinct.
What size are yours? Not certain but I'm thinking the one on the right in the second couple of photos might be male, partly based on head and mouth. One on left, not sure.