I bought this female red wagtail platy - no pictures - yesterday from an unsexed batch at my local petshop. She is in with three guppies and two male platys. She keeps chasing the males away when they come near her, and she is a fair bit fatter than them. How pregnant do you think she is? She was in with males before I got her. I don't want to catch her to have a look at her - the walls of her aquarium aren't seethrough, only the roof - because as I said, I only got her yesterday and she is probably stressed enough as it is.