guppies' eggs are fertilized or not?

[cutie_dinokun]

i have 2 female guppies, 1 has a black gravid spot, and 1 doesn't~ and they are both in the same tank w/a male. So i'm wondering, is it when a female guppy DID mate w/a male, it will turn her gravid spot black, and if she still haven't, then there's no gravid spot visible on her? (btw, both female guppies' stumache is about the same size)

 

[cheirodon]

The so called gravid spot is nothing more than the actual fry, still unborn, visible through her transparent lower tummy. Some females have a dark spot that will be mistaken with them being pregnant, so the surest way to know if a female is pregnant is from her belly size. Believe me, you'll know! And close to giving birth, the belly becomes almost square. She will vaguely resemble a hippopotamus in proportions.

As to the other female not having it, insemination is not always a sure thing. Maybe the female is sterile, maybe she is too young, maybe they just haven't "done it" successfully yet. Gotta wait 'n see...

Good luck!

 

[rsz]

She will vaguely resemble a hippopotamus in proportions.

i just like the idea of a hippo swimming around with a long fancy tail