Welcome to the community Joanne wynn!
You will see the area near the anal vent above and in front of, in the low abdomen getting larger and darker. You will see the body of the momma fish getting more square and glossy looking as they get larger and ready to have babies.
The answer is it is possible it has a slight tannish brown shadow there. If there are male and females, they WILL get pregnant. About 28 days gestation.