I wasn't sure where to post this. My teacher just gave me his mosquito fish and guppies to keep (or just for the summer if I end up not liking them too much).
He thought one of the female guppies was pregnant (there is a male and female guppy, + 4 mosquito fish) so he put her in a breeding tank for a week, nothing happened. This was about a month or two ago.
I just read that the gestation period from guppies is from 20-50 days, depending on the conditions. After just looking it up information about pregnant guppies I learned that they have this dark spot behind their rib cages called a Gravid Spot. I'm pretty sure that she has this spot.
Is there any other way to tell if she is pregnant? She is incredibly fat compared to the male.