Hi, I'm new and is my platy pregnant?

You guys are great, thanks for all the info, I am so much more educated on fish...except for the ball, though LOL yeah its a plastic one, and was not very expensive, it has holes for the fry to go in, and the bigger fish cant. I have one little golden fry- no idea on that one, except there was 5 at the beginning.
Parents unknown.

i took a photo of my tank, its 150 litres. 48 gallons I think.
I have set up a new small tank 5 gallons. For the pregnant females. Should be optimal conditions by tomorrow :) Have put some sponge around the filter so it doesn;t suck fry up.
I thank you so much for the good responses. Yellow one looks like her belly is changing shape, so I am excited at breeding my first fish :D

http://s84.photobucket.com/albums/k1/ducatigirl67/My%20pets/
 
It's a boy, girl, boy, girl...(Is my platy pregnant?)

As others mentioned, a separate tank while waiting for mom to drop the fry is probably your best bet if you intend on raising them

I am happy to announce 4 days after posting my "Is my platy pregnant?"
She gave birth. I followed the suggestions and put the mother in her own 14 gallon tank. When I got up at 5.30am she had been having them...and eating them. I saw her. So after that, I gently tapped the tank when she was about to eat one, and she stopped, see fish can be trained ;)
So I am now the proud new owner of 25++ fry.
I did a partial water change the day before, her tummy was square (thanks so much for that clue!!!). I put a heap of that floating plant in there and spare filter surrounds(plastic grates for them to hide in).
I'm not sure how many there are until they are bigger.
She was dropping them over 10 hours from what I could tell. As soon as she was swimming around as normal, I put her back in the community tank, to carry on. she is well.

Thanks everyone who gave me suggestions, it certainly was invaluable, and I was successful in breeding my first fish :)

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Yay for baby fish! Congrats!
 
Some places such as petco and petsmart will sell "fake" marimo balls...they let algae grow onto a styrofoam ball and it resembles that of a real marimo ball, but they eventually fall apart in the water which is no good
 
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