Larger Female Guppies.

[ImmortalRav]

Is there any different care for them, besides a normal guppy? I have one that I got yesterday and she is five inches across for her body. She is rather large and squared out so I have her inside of her own tank.

 

[AmtotheBurr]

If she's squared out, she might be pregnant

 

[ImmortalRav]

She is very round, and had babies today. Now it's just a matter of catching them.

 

[Far_King]

What else do you have in the tank the fry are in?
 
If you can leave them there and move the mother to another tank it would be far simpler than trying to move all the fry.

 

[ImmortalRav]

Moved her to a 20 gallon and she popped out 51 fry! 

 

[OldMan47]

If there is plenty of cover in that 20 gallon and only the big female and the fry are present, enough fry will survive. Some nice cover includes java moss, Najas grass (sometimes called guppy grass), and similar dense clumps of growing things. Even a spawning mop, usually used for killie fish, could be used as cover but it will not be as effective.
Java moss clump pictures

 

 
A spawning mop is basically a clump of yarn tied together . You wrap yarn 20 to 40 times around a book or similar object, tie the strands together at one point and cut the yarn at the opposite side of the book. Now you can tie what you have to a cork to float it near the surface and just let the strands of yarn hang in the water. Killie breeders let the fish place eggs in the mop and then remove the whole mop to a place for the eggs to hatch but a mop makes decent enough fry cover if you have no appropriate plants.