A guppy is pregnant for around 27-31 days before having fry. Do you know when she bred last? I can pretty much calculate the day of my guppies usually by every 28-29 days.
ive got 3 pregnant guppies (YEY) and one that seams the most pregnant is getting huuuuuge now, and also he spot is very black and it seams like its spreadnig up her back and also shes getting square.... next few days for me
check in the morning wen the sun is about to come up that is the time most liveberers like yo give birth because that is wen my platy gave birth and it was a day i will never forget ever so look in the mornings ok