I have 2 comments on that short video clip.
1. I really don't think he is pregnant.
2. Calling that domestic platy a Xiphophorus maculatus is pretentious at best. It is a domestic platy, not a wild.
The first pic looks a bit like a male platy that has intestinal worms, (Camallanus). This can be treated with Levamisole Hydrochloride or Flubenol. Flubenol is the better option as it treats all intestinal worms. Levamisole only treats certain threadworms.
Camallanus is identified by little red hair like things hanging out the fish's bum.
Let me give you a quick primer Reeqz.
I have pictures of another common livebearer that shows its sex the same as a platy. Notice the bottom fin on this male.
Now notice the same fin on this female.
The same fin difference exists in platies, mollies, guppies, swordtails and endlers but not in all livebearers. Goodeids are an entirely different thing.