Anyway Of Telling......

[samyboy]

how far into the pregnancy a guppy is

they were pregnant when i bought them and they look like there ready to burst and i could do with moving them to another tank im sure the other inhabitants will soon polish them off once born

 

[Annastasia]

There is no surefire way. How dark the gravid spot is, and how fat they are, are basically the only things to go by.

 

[chibi]

Annastasia is right. Make sure the spot is DARK, though. Females will have spots on their belly even if they're not carrying any fry. Their fatness is also another way to tell.

 

[tophat665]

The gravid spot on a guppy is just a sign of sexual maturity. The way to tell if your guppy is ready to pop is when they start to get squarish. Really fat is one thing, but right before they spawn, their contour changes from Volkswagen Beetle to 1985 Volvo Sedan.