At what age male swordtail fry start developing sword?

[Aniket]

I have 25 swordtail fry. They are 4 month old but none of them showing sword tail. I think sometimes they are cross of molly and swordtail because their colour patterns are different. They have more black color on both sides and dark orange on face and tail mostly. I read that molly and swordtail can not get crossed but i dont think so sometimes.

 

[Colin_T]

Mollies and swordtails cannot hybridise because they are in different genus.

Swordtails come in a wide range of colours.

If the fry were well fed and cared for form a young age, the males start to develop the fin filament when about 3-4 months old. But if they are not fed well they can take 6-12 months to grow it.

 

[Aniket]

Mollies and swordtails cannot hybridise because they are in different genus.

Swordtails come in a wide range of colours.

If the fry were well fed and cared for form a young age, the males start to develop the fin filament when about 3-4 months old. But if they are not fed well they can take 6-12 months to grow it.

I feed them 3 types of food mix together 2 times a day.