Genderless Guppies?!

[Guppyguy123]

So i have a litter of guppies that are now 9 months old... The females are all green tailed and the males are yellow with black spots on their tails... But 5 of the 20 fry have no gonopodium or gravid spot! They have similar colours to their male brothers but appear to have no gender! Are they just late developers? All of their brothers and sisters developed their gonopodiums/gravid spots at 3 months old... Are they just mutations or very late developers?!

 

[fish48]

[SIZE=10.5pt] at 9 months old it is unlikely that They are all late developers the chances are they are female[/SIZE]

 

[VickyChaiTea]

Probably just female. Pics?

 

[Dreamer03]

They probable are females.

 

[Baccus]

I have had guppies take twelve months to finally settle on a gender. It could be a survival technique, since I have also found that at cooler water temps the males tend to die off before females. It could also be something to do with the pheromones that are being released by other mature males in the tank supressing the development of younger males.
 
I know its not fish related but I have seen first hand how the hormones released by an adult male rat supressed the growth of another younger male rat that was not even kept with the adult breeding male. The two males where separated by a 4ft tank that housed adult female rats but still the younger male only fully developed and grew to full size once the adult male died from old age. I suspect that this same release of hormones would work on fish in water especially since water is a better conductor of scents and fish are hormone/ pheromone tuned.