I have a few guppies raised from fry in a 10 gallon - one male and three female. Wondering if these females are pregnant or if I am overfeeding - they are about 3 1/2 months old and just keep getting bigger but no fry. Do they look pregnant or overfed? Can the gravid spot get stretched out if they're overweight, or only during pregnancy? They like to pick off the blackworms that live in the substrate so I worry about bloating. I'm very new to guppies and want to make sure they are healthy. Thanks!