Questions

[FishySarah]

I have three 10-12 week old platy fry. I want to keep a male. Two appear female, and one I can't tell. He looks like an undeveloped male or a female with an extra pointy fin. I do have an adult male platy. Are platys like mollies- the males do not show their um...male parts..as early if there is another male around? Thing is I really want another male platy- how long til I will be able to tell, and when will he (if it is a he) become fertile? My one adult male that I have has never impregnated a female in eight months of being with four (I think there's something wrong with him. or he just, uh, marches to a different drummer) and I really need a fertile male.

 

[theotheragentm]

Yup. The presence of a mature male may slow the development of other males. Fish that looks like semi-males are likely to be males. They just haven't full developed. All young fish tend to look female to begin with in life. Three months or thereabouts is when males should become sexually mature. It could take longer too, maybe four months. I haven't seen a set point that people agree on or that I have seen either.

 

[helterskelter]

If your adult male is not displaying to the females and showing off then you fry will mature at 3-4 months, but a strong male doing lots of displaying can suppress young males so the get larger and stronger before they become mature to give them a better chance of breeding later.

These suppressed fish are the best males but these in platies have been known to take 8-10 months and swords and mollies have taken longer and seen fish finally sex out at around 12 months.

 

[FishySarah]

Well my fry are around three months old, but he is not fully developed yet, so it may be a little longer. I'm not sure what you mean by displaying, but my adult male does not really seem interested in my females. I've never seen him chase them or anything, and had no pregnancies by him. I will have to wait and see.