Doing a search on the internet it seems that consultations about whether a female platy is either pregnant, with dropsy or merely fat are quite frequent, so here is mine.
My platy has been living for 5 months in my tank, and I have gotten a soft spot for her since she is the sole survivor of the original 4 platy I got, even when she seemed the weakest of the bunch and the most likely to die. She has grown considerably in lenght (I estimate she's 5,5 cm long now) and her color and vigour has been quite remarkable; however, in the last weeks she has gotten very fat and now she's round enough to look like one of those clay vases and ocasionally, I have seen her sitting on the bottom on a corner, hiding beneath an ornament, although she quickly darts away if I get close.
Her scales don't have the pinecone look of dropsy, and she doesn't seem to have swim bladder issues either. She tends to stay in the same space for some time, and then she swims to other place. Here are some photos:
It isn't very clear in the pictures, but near her anal fin her body has a darker orange tone. The male platy I have (a survivor fry, not sure if his son or not) is quite slender:
My platy has probably had fry before but it has been like three or four months since that. Can they hold male sperm for that long?
PD: sorry if pictures are blurry, but I'm sure I was able to upload bigger pictures before. Has the max size shrunk recently? A shame since posting great fish pictures is one of the big appeals of fish forums.