Are My Platies Pregnant Or Just Fat? & Is This Normal?

[BlueOrchide190]

Hello! I need some insight...
 
I have 2 female platy that I purchased at different times during the last 3 weeks. One is a blue mickey mouse platy, and the other.... I'm not sure, lol. It looks like this, though: http/www.plantedtank.net/forums/images/fish/785_Platy_Xiphophorus_maculatus.e.jpg .
 
I'm wondering if both of my platies could be pregnant??.... My spotted one is my "oldest". It's been getting larger and larger every day, it seems. And the other one I just bought a few days ago. It's got an obvious black spot near her bum, but I'm not sure if it's a "gravid" spot or not...Maybe it's just poop? I don't know, lol. All the fish in the tank at the store seemed to have a spot like hers; even the males. And my first female doesn't really seem to have anything like the gravid spot, in my opinion. Near her bum, there does seem to be SOMETHING there, but nothing like other pictures I've seen. It almost looks uneven in there and splotchy?... I don't know; it's hard to explain, lol. So, I'm not sure what to think about either of my fishy-friends. My MM platy seems to be sticking close to my planted area lately - actually hanging out within the foilage. The spotted one kind of does, too, but she's still pretty open around the tank. The MM seems to be nipping at my spotted girl from time to time today, which is new. Otherwise, they either leave each other alone, or are civil.
 
Something else that I'm wondering about is, my spotted platy from time to time swims kind of strange. Kind of bolting around the tank, swiming/floating kind of on an angle. Like, side ways?... Also, she twists into a sort of sideways "S" shape, and rubs up against the leaves of the plants or the tank. Is this normal behaviour?... Nothing else seems wrong with her, other than my question her pregnancy. And all other things aside, she seems happy.
 
I'm going to try and attatch a few pictures of my platies to show you what I mean. So could you help me out?... Are these ladies preggers?? I have a 2 part nursary for them if they are (a large, plastic floating tank with the trap at the bottom that keep the fry safe). It looks like this, minus the cover and it suction-cups to the tank: http/www.petco.com/assets/product_images/0/010838102555C.jpg .
 
Please help!! These thoughts and questions are driving me crazy, LOL

I hope I'm making some kind of sense in all this.
Thank you in advance!! xx
 
Below are the pictures of my Blue Mickey Mouse Platy. Pregnant? Gravid spot?... Tell me! lol ~

**ADDED**
Here are the pictures of my Spotted Platy. Is she preggers, too? Just fat? I know I don't over feed my fish. I feed them tropical fish flakes in the morning and at night. Sometimes (at least once a week) I only feed them once a day, in the afternoon. I also don't load the tank with flakes.... Speaking of flakes, please excuse the "messy state" of my tank in the pics. I just started feeding them and that seemed LIKE the best time to take the photos

I also turn off the filter during feeding time because otherwise the flakes fly everywhere and don't get eaten, etc. But, yeah.
 
Anyway, thanks in advance! PLEASE HELP!! lol. xx
 
Image 1: http/i1054.photobucket.com/albums/s498/BlueOrchide190/20130620_102531_zpsacff795d.jpg
Image 2: http/i1054.photobucket.com/albums/s498/BlueOrchide190/20130620_102442_zpsb23aff5e.jpg
Image 3: http/i1054.photobucket.com/albums/s498/BlueOrchide190/20130620_102409_zps449c1ff2.jpg

 

[Ny82]

Hi there, the spotted one does look like she is pregnant. I however can never tell with mine and always miss the drop lol. A gravid spot isn't very reliable to tell if a female is pregnant, my 3 week old fry have gravid spots, it usually just indicates female. When they get to the final stages, they go square, that's when you know it's not going to be long. 
I would feed them once a day or you will get ammonia spikes and get the excess flakes back out. 
I don't like using the breeder traps, I have had many a female die in there just from the stress. Let them have their fry in the comfort of their own tank and any fry you see, catch them with a turkey baster and put them into a separate tank - that's what I do. You can also put them into the trap once you catch them. 
Now for some questions to you! How big is your tank, how long has your tank been set up and was it cycled? Swimming at an angle or erratic swimming could be swim bladder disease. Peas sometimes helps with this, but in my experience, once they have it, they rarely recover. I found that when I first got my platies, they were very shy and just hid. 
Swimming against a plant is called flashing. This usually occurs when there is something irritating them. A little flashing is ok but if it's happening a lot then I would test the water, do a water change and see if it relieves her. 

 

[lolobunnz]

They look normal and healrhy to me. The one I can tell is preg is the white one with black spots. The others don't look preg or at least very newly preg.

If they are fat the front of their abdomen gets very large and round, not so much by the baby making area in the back.