Bird or bloke?

[On_a_dishy]

My lovely 4 surviving betta fry will be 4 weeks old this week and I'm excited to think about what they will be in terms of sex.
One is notably smaller than the other 3. It is also paler and "prettier", although that is, of course, me projecting my thoughts that she might be a female. The horizontal "line" through the tails of the other 3 are a good mm longer than the little one's.
They have been having several 25% - 50% water changes a day to dilute the hormone that the males produce, and they have shared the same accommodation since they were eggs.
Have I ended up with 3 males and 1 female, or am I being ridiculously early in trying to guess?
They are all starting to nose up to each other and have little darting chases, so there's no discernible difference in behaviour yet.

 

[PheonixKingZ]

@EllRog may be able to ID gender for you?

Cute little baby Bettas! Do you have pictures of the dad and mom?

 

[On_a_dishy]

I do have pictures! I have so many pictures!
Dad is a red veil tail (Jarvis), and mum is my beautiful koi, Lily. The middle picture is the bubble nest with Jarvis cruising underneath it.
The babies really are cute. They were just eyes on stalks for what seemed like an eternity, but this last week they have developed that betta personality. They have taken over my life.

 

[Colin_T]

What hormone that the males produce?

If they are only a month old they are too young to sex.

 

[On_a_dishy]

I read about growth inhibiting hormones on a betta website, and then one of the staff at my LFS recommended regular water changes because of it. And then a lady who owns another LFS mentioned it when I was asking about when to jar them. Is it a fish-myth? I hope so, because I could do without these water changes!
Maybe the little one's markings are going to be koi and the darker ones more like their red dad. It's so exciting.

 

[Colin_T]

Fish fry do produce hormones that inhibit the growth of other fry around them but it's not just males that produce it, females do too.